diff --git a/nanobot/channels/feishu.py b/nanobot/channels/feishu.py
index 060ba2bb5..381554347 100644
--- a/nanobot/channels/feishu.py
+++ b/nanobot/channels/feishu.py
@@ -1,5 +1,7 @@
 """Feishu/Lark channel implementation using lark-oapi SDK with WebSocket long connection."""
 
+from __future__ import annotations
+
 import asyncio
 import importlib.util
 import json
@@ -11,10 +13,8 @@ import uuid
 from collections import OrderedDict
 from contextlib import suppress
 from dataclasses import dataclass
-from typing import Any, Literal
+from typing import TYPE_CHECKING, Any, Literal
 
-from lark_oapi.api.im.v1.model import MentionEvent, P2ImMessageReceiveV1
-from lark_oapi.core.const import FEISHU_DOMAIN, LARK_DOMAIN
 from pydantic import Field
 
 from nanobot.bus.events import OutboundMessage
@@ -25,8 +25,42 @@ from nanobot.config.schema import Base
 from nanobot.utils.helpers import safe_filename
 from nanobot.utils.logging_bridge import redirect_lib_logging
 
+if TYPE_CHECKING:
+    from lark_oapi.api.im.v1.model import MentionEvent, P2ImMessageReceiveV1
+
 FEISHU_AVAILABLE = importlib.util.find_spec("lark_oapi") is not None
 
+
+def _load_lark_runtime() -> tuple[Any, str, str]:
+    """Import the heavy Feishu SDK lazily.
+
+    lark_oapi imports a large generated API surface at module import time, so
+    keep it out of channel discovery and constructor paths.
+    """
+    import sys
+
+    ws_client_already_imported = "lark_oapi.ws.client" in sys.modules
+    import lark_oapi as lark
+    import lark_oapi.ws.client as lark_ws_client
+    from lark_oapi.core.const import FEISHU_DOMAIN, LARK_DOMAIN
+
+    if (
+        not ws_client_already_imported
+        and threading.current_thread() is not threading.main_thread()
+    ):
+        import_loop = getattr(lark_ws_client, "loop", None)
+        if (
+            import_loop is not None
+            and not import_loop.is_running()
+            and not import_loop.is_closed()
+        ):
+            import_loop.close()
+        lark_ws_client.loop = None
+        with suppress(Exception):
+            asyncio.set_event_loop(None)
+
+    return lark, FEISHU_DOMAIN, LARK_DOMAIN
+
 # Message type display mapping
 MSG_TYPE_MAP = {
     "image": "[image]",
@@ -297,13 +331,11 @@ class FeishuChannel(BaseChannel):
         return FeishuConfig().model_dump(by_alias=True)
 
     def __init__(self, config: Any, bus: MessageBus):
-        import lark_oapi as lark
-
         if isinstance(config, dict):
             config = FeishuConfig.model_validate(config)
         super().__init__(config, bus)
         self.config: FeishuConfig = config
-        self._client: lark.Client = None
+        self._client: Any = None
         self._ws_client: Any = None
         self._ws_thread: threading.Thread | None = None
         self._processed_message_ids: OrderedDict[str, None] = OrderedDict()  # Ordered dedup cache
@@ -329,7 +361,7 @@ class FeishuChannel(BaseChannel):
             self.logger.error("app_id and app_secret not configured")
             return
 
-        import lark_oapi as lark
+        lark, feishu_domain, lark_domain = await asyncio.to_thread(_load_lark_runtime)
 
         redirect_lib_logging("Lark")
 
@@ -337,7 +369,7 @@ class FeishuChannel(BaseChannel):
         self._loop = asyncio.get_running_loop()
 
         # Create Lark client for sending messages
-        domain = LARK_DOMAIN if self.config.domain == "lark" else FEISHU_DOMAIN
+        domain = lark_domain if self.config.domain == "lark" else feishu_domain
         self._client = (
             lark.Client.builder()
             .app_id(self.config.app_id)
@@ -397,6 +429,7 @@ class FeishuChannel(BaseChannel):
 
             import lark_oapi.ws.client as _lark_ws_client
 
+            previous_loop = getattr(_lark_ws_client, "loop", None)
             ws_loop = asyncio.new_event_loop()
             asyncio.set_event_loop(ws_loop)
             # Patch the module-level loop used by lark's ws Client.start()
@@ -410,6 +443,10 @@ class FeishuChannel(BaseChannel):
                     if self._running:
                         time.sleep(5)
             finally:
+                if getattr(_lark_ws_client, "loop", None) is ws_loop:
+                    _lark_ws_client.loop = previous_loop
+                with suppress(Exception):
+                    asyncio.set_event_loop(None)
                 ws_loop.close()
 
         self._ws_thread = threading.Thread(target=run_ws, daemon=True)
diff --git a/tests/channels/test_feishu_lazy_import.py b/tests/channels/test_feishu_lazy_import.py
new file mode 100644
index 000000000..d43c39ebb
--- /dev/null
+++ b/tests/channels/test_feishu_lazy_import.py
@@ -0,0 +1,46 @@
+import subprocess
+import sys
+
+
+def _run_import_probe(source: str) -> str:
+    proc = subprocess.run(
+        [sys.executable, "-c", source],
+        check=True,
+        capture_output=True,
+        text=True,
+    )
+    return proc.stdout.strip()
+
+
+def test_feishu_module_import_does_not_import_lark_oapi():
+    out = _run_import_probe(
+        "import sys; import nanobot.channels.feishu; print('lark_oapi' in sys.modules)"
+    )
+
+    assert out == "False"
+
+
+def test_feishu_channel_constructor_does_not_import_lark_oapi():
+    out = _run_import_probe(
+        "import sys; "
+        "from nanobot.bus.queue import MessageBus; "
+        "from nanobot.channels.feishu import FeishuChannel; "
+        "FeishuChannel({'enabled': True}, MessageBus()); "
+        "print('lark_oapi' in sys.modules)"
+    )
+
+    assert out == "False"
+
+
+def test_lark_runtime_thread_import_clears_sdk_import_loop():
+    out = _run_import_probe(
+        "import asyncio\n"
+        "from nanobot.channels.feishu import _load_lark_runtime\n"
+        "async def main():\n"
+        "    await asyncio.to_thread(_load_lark_runtime)\n"
+        "    import lark_oapi.ws.client as ws\n"
+        "    print(getattr(ws, 'loop', 'sentinel') is None)\n"
+        "asyncio.run(main())"
+    )
+
+    assert out == "True"