diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..5c26f48
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,7 @@
+"""
+测试包根目录。
+
+让 `tests.*` 模块可以被正常 import（例如给 `unilabos` 下的测试入口使用）。
+"""
+
+
diff --git a/tests/devices/__init__.py b/tests/devices/__init__.py
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/tests/devices/__init__.py
@@ -0,0 +1 @@
+
diff --git a/tests/devices/liquid_handling/__init__.py b/tests/devices/liquid_handling/__init__.py
new file mode 100644
index 0000000..b16b30e
--- /dev/null
+++ b/tests/devices/liquid_handling/__init__.py
@@ -0,0 +1,5 @@
+"""
+液体处理设备相关测试。
+"""
+
+
diff --git a/tests/devices/liquid_handling/test_transfer_liquid.py b/tests/devices/liquid_handling/test_transfer_liquid.py
new file mode 100644
index 0000000..9896aac
--- /dev/null
+++ b/tests/devices/liquid_handling/test_transfer_liquid.py
@@ -0,0 +1,505 @@
+import asyncio
+from dataclasses import dataclass
+from typing import Any, Iterable, List, Optional, Sequence, Tuple
+
+import pytest
+
+from unilabos.devices.liquid_handling.liquid_handler_abstract import LiquidHandlerAbstract
+
+
+@dataclass(frozen=True)
+class DummyContainer:
+    name: str
+
+    def __repr__(self) -> str:  # pragma: no cover
+        return f"DummyContainer({self.name})"
+
+
+@dataclass(frozen=True)
+class DummyTipSpot:
+    name: str
+
+    def __repr__(self) -> str:  # pragma: no cover
+        return f"DummyTipSpot({self.name})"
+
+
+def make_tip_iter(n: int = 256) -> Iterable[List[DummyTipSpot]]:
+    """Yield lists so code can safely call `tip.extend(next(self.current_tip))`."""
+    for i in range(n):
+        yield [DummyTipSpot(f"tip_{i}")]
+
+
+class FakeLiquidHandler(LiquidHandlerAbstract):
+    """不初始化真实 backend/deck；仅用来记录 transfer_liquid 内部调用序列。"""
+
+    def __init__(self, channel_num: int = 8):
+        # 不调用 super().__init__，避免真实硬件/后端依赖
+        self.channel_num = channel_num
+        self.support_touch_tip = True
+        self.current_tip = iter(make_tip_iter())
+        self.calls: List[Tuple[str, Any]] = []
+
+    async def pick_up_tips(self, tip_spots, use_channels=None, offsets=None, **backend_kwargs):
+        self.calls.append(("pick_up_tips", {"tips": list(tip_spots), "use_channels": use_channels}))
+
+    async def aspirate(
+        self,
+        resources: Sequence[Any],
+        vols: List[float],
+        use_channels: Optional[List[int]] = None,
+        flow_rates: Optional[List[Optional[float]]] = None,
+        offsets: Any = None,
+        liquid_height: Any = None,
+        blow_out_air_volume: Any = None,
+        spread: str = "wide",
+        **backend_kwargs,
+    ):
+        self.calls.append(
+            (
+                "aspirate",
+                {
+                    "resources": list(resources),
+                    "vols": list(vols),
+                    "use_channels": list(use_channels) if use_channels is not None else None,
+                    "flow_rates": list(flow_rates) if flow_rates is not None else None,
+                    "offsets": list(offsets) if offsets is not None else None,
+                    "liquid_height": list(liquid_height) if liquid_height is not None else None,
+                    "blow_out_air_volume": list(blow_out_air_volume) if blow_out_air_volume is not None else None,
+                },
+            )
+        )
+
+    async def dispense(
+        self,
+        resources: Sequence[Any],
+        vols: List[float],
+        use_channels: Optional[List[int]] = None,
+        flow_rates: Optional[List[Optional[float]]] = None,
+        offsets: Any = None,
+        liquid_height: Any = None,
+        blow_out_air_volume: Any = None,
+        spread: str = "wide",
+        **backend_kwargs,
+    ):
+        self.calls.append(
+            (
+                "dispense",
+                {
+                    "resources": list(resources),
+                    "vols": list(vols),
+                    "use_channels": list(use_channels) if use_channels is not None else None,
+                    "flow_rates": list(flow_rates) if flow_rates is not None else None,
+                    "offsets": list(offsets) if offsets is not None else None,
+                    "liquid_height": list(liquid_height) if liquid_height is not None else None,
+                    "blow_out_air_volume": list(blow_out_air_volume) if blow_out_air_volume is not None else None,
+                },
+            )
+        )
+
+    async def discard_tips(self, use_channels=None, *args, **kwargs):
+        # 有的分支是 discard_tips(use_channels=[0])，有的分支是 discard_tips([0..7])（位置参数）
+        self.calls.append(("discard_tips", {"use_channels": list(use_channels) if use_channels is not None else None}))
+
+    async def custom_delay(self, seconds=0, msg=None):
+        self.calls.append(("custom_delay", {"seconds": seconds, "msg": msg}))
+
+    async def touch_tip(self, targets):
+        # 原实现会访问 targets.get_size_x() 等；测试里只记录调用
+        self.calls.append(("touch_tip", {"targets": targets}))
+
+    async def mix(self, targets, mix_time=None, mix_vol=None, height_to_bottom=None, offsets=None, mix_rate=None, none_keys=None):
+        self.calls.append(
+            (
+                "mix",
+                {
+                    "targets": targets,
+                    "mix_time": mix_time,
+                    "mix_vol": mix_vol,
+                },
+            )
+        )
+
+
+def run(coro):
+    return asyncio.run(coro)
+
+
+def test_one_to_one_single_channel_basic_calls():
+    lh = FakeLiquidHandler(channel_num=1)
+    lh.current_tip = iter(make_tip_iter(64))
+
+    sources = [DummyContainer(f"S{i}") for i in range(3)]
+    targets = [DummyContainer(f"T{i}") for i in range(3)]
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=targets,
+            tip_racks=[],
+            use_channels=[0],
+            asp_vols=[1, 2, 3],
+            dis_vols=[4, 5, 6],
+            mix_times=None,  # 应该仍能执行（不 mix）
+        )
+    )
+
+    assert [c[0] for c in lh.calls].count("pick_up_tips") == 3
+    assert [c[0] for c in lh.calls].count("aspirate") == 3
+    assert [c[0] for c in lh.calls].count("dispense") == 3
+    assert [c[0] for c in lh.calls].count("discard_tips") == 3
+
+    # 每次 aspirate/dispense 都是单孔列表
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    assert aspirates[0]["resources"] == [sources[0]]
+    assert aspirates[0]["vols"] == [1.0]
+
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert dispenses[2]["resources"] == [targets[2]]
+    assert dispenses[2]["vols"] == [6.0]
+
+
+def test_one_to_one_single_channel_before_stage_mixes_prior_to_aspirate():
+    lh = FakeLiquidHandler(channel_num=1)
+    lh.current_tip = iter(make_tip_iter(16))
+
+    source = DummyContainer("S0")
+    target = DummyContainer("T0")
+
+    run(
+        lh.transfer_liquid(
+            sources=[source],
+            targets=[target],
+            tip_racks=[],
+            use_channels=[0],
+            asp_vols=[5],
+            dis_vols=[5],
+            mix_stage="before",
+            mix_times=1,
+            mix_vol=3,
+        )
+    )
+
+    names = [name for name, _ in lh.calls]
+    assert names.count("mix") == 1
+    assert names.index("mix") < names.index("aspirate")
+
+
+def test_one_to_one_eight_channel_groups_by_8():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(256))
+
+    sources = [DummyContainer(f"S{i}") for i in range(16)]
+    targets = [DummyContainer(f"T{i}") for i in range(16)]
+    asp_vols = list(range(1, 17))
+    dis_vols = list(range(101, 117))
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=targets,
+            tip_racks=[],
+            use_channels=list(range(8)),
+            asp_vols=asp_vols,
+            dis_vols=dis_vols,
+            mix_times=0,  # 触发逻辑但不 mix
+        )
+    )
+
+    # 16 个任务 -> 2 组，每组 8 通道一起做
+    assert [c[0] for c in lh.calls].count("pick_up_tips") == 2
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert len(aspirates) == 2
+    assert len(dispenses) == 2
+
+    assert aspirates[0]["resources"] == sources[0:8]
+    assert aspirates[0]["vols"] == [float(v) for v in asp_vols[0:8]]
+    assert dispenses[1]["resources"] == targets[8:16]
+    assert dispenses[1]["vols"] == [float(v) for v in dis_vols[8:16]]
+
+
+def test_one_to_one_eight_channel_requires_multiple_of_8_targets():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(64))
+
+    sources = [DummyContainer(f"S{i}") for i in range(9)]
+    targets = [DummyContainer(f"T{i}") for i in range(9)]
+
+    with pytest.raises(ValueError, match="multiple of 8"):
+        run(
+            lh.transfer_liquid(
+                sources=sources,
+                targets=targets,
+                tip_racks=[],
+                use_channels=list(range(8)),
+                asp_vols=[1] * 9,
+                dis_vols=[1] * 9,
+                mix_times=0,
+            )
+        )
+
+
+def test_one_to_one_eight_channel_parameter_lists_are_chunked_per_8():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(512))
+
+    sources = [DummyContainer(f"S{i}") for i in range(16)]
+    targets = [DummyContainer(f"T{i}") for i in range(16)]
+    asp_vols = [i + 1 for i in range(16)]
+    dis_vols = [200 + i for i in range(16)]
+    asp_flow_rates = [0.1 * (i + 1) for i in range(16)]
+    dis_flow_rates = [0.2 * (i + 1) for i in range(16)]
+    offsets = [f"offset_{i}" for i in range(16)]
+    liquid_heights = [i * 0.5 for i in range(16)]
+    blow_out_air_volume = [i + 0.05 for i in range(16)]
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=targets,
+            tip_racks=[],
+            use_channels=list(range(8)),
+            asp_vols=asp_vols,
+            dis_vols=dis_vols,
+            asp_flow_rates=asp_flow_rates,
+            dis_flow_rates=dis_flow_rates,
+            offsets=offsets,
+            liquid_height=liquid_heights,
+            blow_out_air_volume=blow_out_air_volume,
+            mix_times=0,
+        )
+    )
+
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert len(aspirates) == len(dispenses) == 2
+
+    for batch_idx in range(2):
+        start = batch_idx * 8
+        end = start + 8
+        asp_call = aspirates[batch_idx]
+        dis_call = dispenses[batch_idx]
+        assert asp_call["resources"] == sources[start:end]
+        assert asp_call["flow_rates"] == asp_flow_rates[start:end]
+        assert asp_call["offsets"] == offsets[start:end]
+        assert asp_call["liquid_height"] == liquid_heights[start:end]
+        assert asp_call["blow_out_air_volume"] == blow_out_air_volume[start:end]
+        assert dis_call["flow_rates"] == dis_flow_rates[start:end]
+        assert dis_call["offsets"] == offsets[start:end]
+        assert dis_call["liquid_height"] == liquid_heights[start:end]
+        assert dis_call["blow_out_air_volume"] == blow_out_air_volume[start:end]
+
+
+def test_one_to_one_eight_channel_handles_32_tasks_four_batches():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(1024))
+
+    sources = [DummyContainer(f"S{i}") for i in range(32)]
+    targets = [DummyContainer(f"T{i}") for i in range(32)]
+    asp_vols = [i + 1 for i in range(32)]
+    dis_vols = [300 + i for i in range(32)]
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=targets,
+            tip_racks=[],
+            use_channels=list(range(8)),
+            asp_vols=asp_vols,
+            dis_vols=dis_vols,
+            mix_times=0,
+        )
+    )
+
+    pick_calls = [name for name, _ in lh.calls if name == "pick_up_tips"]
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert len(pick_calls) == 4
+    assert len(aspirates) == len(dispenses) == 4
+    assert aspirates[0]["resources"] == sources[0:8]
+    assert aspirates[-1]["resources"] == sources[24:32]
+    assert dispenses[0]["resources"] == targets[0:8]
+    assert dispenses[-1]["resources"] == targets[24:32]
+
+
+def test_one_to_many_single_channel_aspirates_total_when_asp_vol_too_small():
+    lh = FakeLiquidHandler(channel_num=1)
+    lh.current_tip = iter(make_tip_iter(64))
+
+    source = DummyContainer("SRC")
+    targets = [DummyContainer(f"T{i}") for i in range(3)]
+    dis_vols = [10, 20, 30]  # sum=60
+
+    run(
+        lh.transfer_liquid(
+            sources=[source],
+            targets=targets,
+            tip_racks=[],
+            use_channels=[0],
+            asp_vols=10,  # 小于 sum(dis_vols) -> 应吸 60
+            dis_vols=dis_vols,
+            mix_times=0,
+        )
+    )
+
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    assert len(aspirates) == 1
+    assert aspirates[0]["resources"] == [source]
+    assert aspirates[0]["vols"] == [60.0]
+    assert aspirates[0]["use_channels"] == [0]
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert [d["vols"][0] for d in dispenses] == [10.0, 20.0, 30.0]
+
+
+def test_one_to_many_eight_channel_basic():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(128))
+
+    source = DummyContainer("SRC")
+    targets = [DummyContainer(f"T{i}") for i in range(8)]
+    dis_vols = [i + 1 for i in range(8)]
+
+    run(
+        lh.transfer_liquid(
+            sources=[source],
+            targets=targets,
+            tip_racks=[],
+            use_channels=list(range(8)),
+            asp_vols=999,  # one-to-many 8ch 会按 dis_vols 吸（每通道各自）
+            dis_vols=dis_vols,
+            mix_times=0,
+        )
+    )
+
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    assert aspirates[0]["resources"] == [source] * 8
+    assert aspirates[0]["vols"] == [float(v) for v in dis_vols]
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert dispenses[0]["resources"] == targets
+    assert dispenses[0]["vols"] == [float(v) for v in dis_vols]
+
+
+def test_many_to_one_single_channel_standard_dispense_equals_asp_by_default():
+    lh = FakeLiquidHandler(channel_num=1)
+    lh.current_tip = iter(make_tip_iter(128))
+
+    sources = [DummyContainer(f"S{i}") for i in range(3)]
+    target = DummyContainer("T")
+    asp_vols = [5, 6, 7]
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=[target],
+            tip_racks=[],
+            use_channels=[0],
+            asp_vols=asp_vols,
+            dis_vols=1,  # many-to-one 允许标量；非比例模式下实际每次分液=对应 asp_vol
+            mix_times=0,
+        )
+    )
+
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert [d["vols"][0] for d in dispenses] == [float(v) for v in asp_vols]
+    assert all(d["resources"] == [target] for d in dispenses)
+
+
+def test_many_to_one_single_channel_before_stage_mixes_target_once():
+    lh = FakeLiquidHandler(channel_num=1)
+    lh.current_tip = iter(make_tip_iter(128))
+
+    sources = [DummyContainer("S0"), DummyContainer("S1")]
+    target = DummyContainer("T")
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=[target],
+            tip_racks=[],
+            use_channels=[0],
+            asp_vols=[5, 6],
+            dis_vols=1,
+            mix_stage="before",
+            mix_times=2,
+            mix_vol=4,
+        )
+    )
+
+    names = [name for name, _ in lh.calls]
+    assert names[0] == "mix"
+    assert names.count("mix") == 1
+
+
+def test_many_to_one_single_channel_proportional_mixing_uses_dis_vols_per_source():
+    lh = FakeLiquidHandler(channel_num=1)
+    lh.current_tip = iter(make_tip_iter(128))
+
+    sources = [DummyContainer(f"S{i}") for i in range(3)]
+    target = DummyContainer("T")
+    asp_vols = [5, 6, 7]
+    dis_vols = [1, 2, 3]
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=[target],
+            tip_racks=[],
+            use_channels=[0],
+            asp_vols=asp_vols,
+            dis_vols=dis_vols,  # 比例模式
+            mix_times=0,
+        )
+    )
+
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert [d["vols"][0] for d in dispenses] == [float(v) for v in dis_vols]
+
+
+def test_many_to_one_eight_channel_basic():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(256))
+
+    sources = [DummyContainer(f"S{i}") for i in range(8)]
+    target = DummyContainer("T")
+    asp_vols = [10 + i for i in range(8)]
+
+    run(
+        lh.transfer_liquid(
+            sources=sources,
+            targets=[target],
+            tip_racks=[],
+            use_channels=list(range(8)),
+            asp_vols=asp_vols,
+            dis_vols=999,  # 非比例模式下每通道分液=对应 asp_vol
+            mix_times=0,
+        )
+    )
+
+    aspirates = [payload for name, payload in lh.calls if name == "aspirate"]
+    dispenses = [payload for name, payload in lh.calls if name == "dispense"]
+    assert aspirates[0]["resources"] == sources
+    assert aspirates[0]["vols"] == [float(v) for v in asp_vols]
+    assert dispenses[0]["resources"] == [target] * 8
+    assert dispenses[0]["vols"] == [float(v) for v in asp_vols]
+
+
+def test_transfer_liquid_mode_detection_unsupported_shape_raises():
+    lh = FakeLiquidHandler(channel_num=8)
+    lh.current_tip = iter(make_tip_iter(64))
+
+    sources = [DummyContainer("S0"), DummyContainer("S1")]
+    targets = [DummyContainer("T0"), DummyContainer("T1"), DummyContainer("T2")]
+
+    with pytest.raises(ValueError, match="Unsupported transfer mode"):
+        run(
+            lh.transfer_liquid(
+                sources=sources,
+                targets=targets,
+                tip_racks=[],
+                use_channels=[0],
+                asp_vols=[1, 1],
+                dis_vols=[1, 1, 1],
+                mix_times=0,
+            )
+        )
+
diff --git a/tests/ros/msgs/test_runner.py b/tests/ros/msgs/test_runner.py
index fe4cb09..02d352d 100644
--- a/tests/ros/msgs/test_runner.py
+++ b/tests/ros/msgs/test_runner.py
@@ -11,10 +11,10 @@ import os
 # 添加项目根目录到路径
 sys.path.append(os.path.dirname(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))))
 
-# 导入测试模块
-from test.ros.msgs.test_basic import TestBasicFunctionality
-from test.ros.msgs.test_conversion import TestBasicConversion, TestMappingConversion
-from test.ros.msgs.test_mapping import TestTypeMapping, TestFieldMapping
+# 导入测试模块（统一从 tests 包获取）
+from tests.ros.msgs.test_basic import TestBasicFunctionality
+from tests.ros.msgs.test_conversion import TestBasicConversion, TestMappingConversion
+from tests.ros.msgs.test_mapping import TestTypeMapping, TestFieldMapping
 
 
 def run_tests():
diff --git a/unilabos/devices/liquid_handling/liquid_handler_abstract.py b/unilabos/devices/liquid_handling/liquid_handler_abstract.py
index 96289ff..d02129c 100644
--- a/unilabos/devices/liquid_handling/liquid_handler_abstract.py
+++ b/unilabos/devices/liquid_handling/liquid_handler_abstract.py
@@ -1042,11 +1042,19 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
             One or more TipRacks providing fresh tips.
         is_96_well
             Set *True* to use the 96‑channel head.
+        mix_stage
+            When to mix the target wells relative to dispensing. Default "none" means
+            no mixing occurs even if mix_times is provided. Use "before", "after", or
+            "both" to mix at the corresponding stage(s).
+        mix_times
+            Number of mix cycles. If *None* (default) no mixing occurs regardless of
+            mix_stage.
         """
         
         # 确保 use_channels 有默认值
         if use_channels is None:
-            use_channels = [0] if self.channel_num >= 1 else list(range(self.channel_num))
+            # 默认使用设备所有通道（例如 8 通道移液站默认就是 0-7）
+            use_channels = list(range(self.channel_num)) if self.channel_num > 0 else [0]
         
         if is_96_well:
             pass  # This mode is not verified.
@@ -1074,42 +1082,42 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
         if mix_times is not None:
             mix_times = int(mix_times)
             
-            # 识别传输模式
-            num_sources = len(sources)
-            num_targets = len(targets)
-            
-            if num_sources == 1 and num_targets > 1:
-                # 模式1: 一对多 (1 source -> N targets)
-                await self._transfer_one_to_many(
-                    sources[0], targets, tip_racks, use_channels,
-                    asp_vols, dis_vols, asp_flow_rates, dis_flow_rates,
-                    offsets, touch_tip, liquid_height, blow_out_air_volume,
-                    spread, mix_stage, mix_times, mix_vol, mix_rate,
-                    mix_liquid_height, delays
-                )
-            elif num_sources > 1 and num_targets == 1:
-                # 模式2: 多对一 (N sources -> 1 target)
-                await self._transfer_many_to_one(
-                    sources, targets[0], tip_racks, use_channels,
-                    asp_vols, dis_vols, asp_flow_rates, dis_flow_rates,
-                    offsets, touch_tip, liquid_height, blow_out_air_volume,
-                    spread, mix_stage, mix_times, mix_vol, mix_rate,
-                    mix_liquid_height, delays
-                )
-            elif num_sources == num_targets:
-                # 模式3: 一对一 (N sources -> N targets) - 原有逻辑
-                await self._transfer_one_to_one(
-                    sources, targets, tip_racks, use_channels,
-                    asp_vols, dis_vols, asp_flow_rates, dis_flow_rates,
-                    offsets, touch_tip, liquid_height, blow_out_air_volume,
-                    spread, mix_stage, mix_times, mix_vol, mix_rate,
-                    mix_liquid_height, delays
-                )
-            else:
-                raise ValueError(
-                    f"Unsupported transfer mode: {num_sources} sources -> {num_targets} targets. "
-                    "Supported modes: 1->N, N->1, or N->N."
-                )
+        # 识别传输模式（mix_times 为 None 也应该能正常移液，只是不做 mix）
+        num_sources = len(sources)
+        num_targets = len(targets)
+        
+        if num_sources == 1 and num_targets > 1:
+            # 模式1: 一对多 (1 source -> N targets)
+            await self._transfer_one_to_many(
+                sources[0], targets, tip_racks, use_channels,
+                asp_vols, dis_vols, asp_flow_rates, dis_flow_rates,
+                offsets, touch_tip, liquid_height, blow_out_air_volume,
+                spread, mix_stage, mix_times, mix_vol, mix_rate,
+                mix_liquid_height, delays
+            )
+        elif num_sources > 1 and num_targets == 1:
+            # 模式2: 多对一 (N sources -> 1 target)
+            await self._transfer_many_to_one(
+                sources, targets[0], tip_racks, use_channels,
+                asp_vols, dis_vols, asp_flow_rates, dis_flow_rates,
+                offsets, touch_tip, liquid_height, blow_out_air_volume,
+                spread, mix_stage, mix_times, mix_vol, mix_rate,
+                mix_liquid_height, delays
+            )
+        elif num_sources == num_targets:
+            # 模式3: 一对一 (N sources -> N targets)
+            await self._transfer_one_to_one(
+                sources, targets, tip_racks, use_channels,
+                asp_vols, dis_vols, asp_flow_rates, dis_flow_rates,
+                offsets, touch_tip, liquid_height, blow_out_air_volume,
+                spread, mix_stage, mix_times, mix_vol, mix_rate,
+                mix_liquid_height, delays
+            )
+        else:
+            raise ValueError(
+                f"Unsupported transfer mode: {num_sources} sources -> {num_targets} targets. "
+                "Supported modes: 1->N, N->1, or N->N."
+            )
 
     async def _transfer_one_to_one(
         self,
@@ -1149,6 +1157,16 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
                     tip.extend(next(self.current_tip))
                 await self.pick_up_tips(tip)
 
+                if mix_stage in ["before", "both"] and mix_times is not None and mix_times > 0:
+                    await self.mix(
+                        targets=[targets[_]],
+                        mix_time=mix_times,
+                        mix_vol=mix_vol,
+                        offsets=offsets if offsets else None,
+                        height_to_bottom=mix_liquid_height if mix_liquid_height else None,
+                        mix_rate=mix_rate if mix_rate else None,
+                    )
+
                 await self.aspirate(
                     resources=[sources[_]],
                     vols=[asp_vols[_]],
@@ -1209,6 +1227,16 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
                 current_dis_blow_out_air_volume = blow_out_air_volume[i:i + 8] if blow_out_air_volume else [None] * 8
                 current_dis_flow_rates = dis_flow_rates[i:i + 8] if dis_flow_rates else None
 
+                if mix_stage in ["before", "both"] and mix_times is not None and mix_times > 0:
+                    await self.mix(
+                        targets=current_targets,
+                        mix_time=mix_times,
+                        mix_vol=mix_vol,
+                        offsets=offsets if offsets else None,
+                        height_to_bottom=mix_liquid_height if mix_liquid_height else None,
+                        mix_rate=mix_rate if mix_rate else None,
+                    )
+
                 await self.aspirate(
                     resources=current_reagent_sources,
                     vols=current_asp_vols,
@@ -1290,6 +1318,17 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
                 tip.extend(next(self.current_tip))
             await self.pick_up_tips(tip)
 
+            if mix_stage in ["before", "both"] and mix_times is not None and mix_times > 0:
+                for idx, target in enumerate(targets):
+                    await self.mix(
+                        targets=[target],
+                        mix_time=mix_times,
+                        mix_vol=mix_vol,
+                        offsets=offsets[idx:idx + 1] if offsets and len(offsets) > idx else None,
+                        height_to_bottom=mix_liquid_height if mix_liquid_height else None,
+                        mix_rate=mix_rate if mix_rate else None,
+                    )
+
             # 从源容器吸液（总体积）
             await self.aspirate(
                 resources=[source],
@@ -1354,6 +1393,16 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
                 current_asp_liquid_height = liquid_height[0:1] * 8 if liquid_height and len(liquid_height) > 0 else [None] * 8
                 current_asp_blow_out_air_volume = blow_out_air_volume[0:1] * 8 if blow_out_air_volume and len(blow_out_air_volume) > 0 else [None] * 8
                 
+                if mix_stage in ["before", "both"] and mix_times is not None and mix_times > 0:
+                    await self.mix(
+                        targets=current_targets,
+                        mix_time=mix_times,
+                        mix_vol=mix_vol,
+                        offsets=offsets[i:i + 8] if offsets else None,
+                        height_to_bottom=mix_liquid_height if mix_liquid_height else None,
+                        mix_rate=mix_rate if mix_rate else None,
+                    )
+                
                 # 从源容器吸液（8个通道都从同一个源，但每个通道的吸液体积不同）
                 await self.aspirate(
                     resources=[source] * 8,  # 8个通道都从同一个源
@@ -1452,8 +1501,14 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
             # 单通道模式：多次吸液，一次分液
             # 先混合前（如果需要）
             if mix_stage in ["before", "both"] and mix_times is not None and mix_times > 0:
-                # 注意：在吸液前混合源容器通常不常见，这里跳过
-                pass
+                await self.mix(
+                    targets=[target],
+                    mix_time=mix_times,
+                    mix_vol=mix_vol,
+                    offsets=offsets[0:1] if offsets else None,
+                    height_to_bottom=mix_liquid_height if mix_liquid_height else None,
+                    mix_rate=mix_rate if mix_rate else None,
+                )
             
             # 从每个源容器吸液并分液到目标容器
             for idx, source in enumerate(sources):
@@ -1528,6 +1583,16 @@ class LiquidHandlerAbstract(LiquidHandlerMiddleware):
                 raise ValueError(f"For 8-channel mode, number of sources {len(sources)} must be a multiple of 8.")
             
             # 每次处理8个源
+            if mix_stage in ["before", "both"] and mix_times is not None and mix_times > 0:
+                await self.mix(
+                    targets=[target],
+                    mix_time=mix_times,
+                    mix_vol=mix_vol,
+                    offsets=offsets[0:1] if offsets else None,
+                    height_to_bottom=mix_liquid_height if mix_liquid_height else None,
+                    mix_rate=mix_rate if mix_rate else None,
+                )
+
             for i in range(0, len(sources), 8):
                 tip = []
                 for _ in range(len(use_channels)):
diff --git a/unilabos/devices/liquid_handling/test_transfer_liquid.py b/unilabos/devices/liquid_handling/test_transfer_liquid.py
new file mode 100644
index 0000000..f13980f
--- /dev/null
+++ b/unilabos/devices/liquid_handling/test_transfer_liquid.py
@@ -0,0 +1,13 @@
+"""
+说明：
+这里放一个“入口文件”，方便在 `unilabos/devices/liquid_handling` 目录下直接找到
+`transfer_liquid` 的测试。
+
+实际测试用例实现放在仓库标准测试目录：
+`tests/devices/liquid_handling/test_transfer_liquid.py`
+"""
+
+# 让 pytest 能从这里发现同一套测试（避免复制两份测试代码）。
+from tests.devices.liquid_handling.test_transfer_liquid import *  # noqa: F401,F403
+
+