diff --git a/nonebot/__init__.py b/nonebot/__init__.py
index 8ee450bd..20ca9113 100644
--- a/nonebot/__init__.py
+++ b/nonebot/__init__.py
@@ -114,12 +114,18 @@ from .helpers import context_id
 
 __all__ = [
     'NoneBot', 'scheduler', 'init', 'get_bot', 'run',
+
     'CQHttpError',
+
     'load_plugin', 'load_plugins', 'load_builtin_plugins',
     'get_loaded_plugins',
+
     'message_preprocessor', 'Message', 'MessageSegment',
+
     'on_command', 'CommandSession', 'CommandGroup',
+
     'on_natural_language', 'NLPSession', 'NLPResult', 'IntentCommand',
     'on_notice', 'NoticeSession', 'on_request', 'RequestSession',
+
     'context_id',
 ]
diff --git a/nonebot/command/__init__.py b/nonebot/command/__init__.py
index be1cfa9e..18010526 100644
--- a/nonebot/command/__init__.py
+++ b/nonebot/command/__init__.py
@@ -156,55 +156,6 @@ def on_command(name: Union[str, CommandName_T], *,
     return deco
 
 
-class CommandGroup:
-    """
-    Group a set of commands with same name prefix.
-    """
-    __slots__ = ('basename', 'permission', 'only_to_me', 'privileged',
-                 'shell_like')
-
-    def __init__(self, name: Union[str, CommandName_T],
-                 permission: Optional[int] = None, *,
-                 only_to_me: Optional[bool] = None,
-                 privileged: Optional[bool] = None,
-                 shell_like: Optional[bool] = None):
-        self.basename = (name,) if isinstance(name, str) else name
-        self.permission = permission  # TODO: use .pyi
-        self.only_to_me = only_to_me
-        self.privileged = privileged
-        self.shell_like = shell_like
-
-    def command(self, name: Union[str, CommandName_T], *,
-                aliases: Optional[Iterable[str]] = None,
-                permission: Optional[int] = None,
-                only_to_me: Optional[bool] = None,
-                privileged: Optional[bool] = None,
-                shell_like: Optional[bool] = None) -> Callable:
-        sub_name = (name,) if isinstance(name, str) else name
-        name = self.basename + sub_name
-
-        kwargs = {}
-        if aliases is not None:
-            kwargs['aliases'] = aliases
-        if permission is not None:
-            kwargs['permission'] = permission
-        elif self.permission is not None:
-            kwargs['permission'] = self.permission
-        if only_to_me is not None:
-            kwargs['only_to_me'] = only_to_me
-        elif self.only_to_me is not None:
-            kwargs['only_to_me'] = self.only_to_me
-        if privileged is not None:
-            kwargs['privileged'] = privileged
-        elif self.privileged is not None:
-            kwargs['privileged'] = self.privileged
-        if shell_like is not None:
-            kwargs['shell_like'] = shell_like
-        elif self.shell_like is not None:
-            kwargs['shell_like'] = self.shell_like
-        return on_command(name, **kwargs)
-
-
 def _find_command(name: Union[str, CommandName_T]) -> Optional[Command]:
     cmd_name = (name,) if isinstance(name, str) else name
     if not cmd_name:
@@ -686,3 +637,6 @@ def kill_current_session(ctx: Context_T) -> None:
     ctx_id = context_id(ctx)
     if ctx_id in _sessions:
         del _sessions[ctx_id]
+
+
+from nonebot.command.group import CommandGroup
diff --git a/nonebot/command/group.py b/nonebot/command/group.py
new file mode 100644
index 00000000..6f7d4ca8
--- /dev/null
+++ b/nonebot/command/group.py
@@ -0,0 +1,26 @@
+from typing import Union, Callable
+
+from nonebot.command import on_command
+from nonebot.typing import CommandName_T
+
+
+class CommandGroup:
+    """
+    Group a set of commands with same name prefix.
+    """
+
+    __slots__ = ('basename', 'base_kwargs')
+
+    def __init__(self, name: Union[str, CommandName_T], **kwargs):
+        self.basename = (name,) if isinstance(name, str) else name
+        if 'aliases' in kwargs:
+            del kwargs['aliases']  # ensure there is no aliases here
+        self.base_kwargs = kwargs
+
+    def command(self, name: Union[str, CommandName_T], **kwargs) -> Callable:
+        sub_name = (name,) if isinstance(name, str) else name
+        name = self.basename + sub_name
+
+        final_kwargs = self.base_kwargs.copy()
+        final_kwargs.update(kwargs)
+        return on_command(name, **final_kwargs)
diff --git a/nonebot/command/group.pyi b/nonebot/command/group.pyi
new file mode 100644
index 00000000..ace431a8
--- /dev/null
+++ b/nonebot/command/group.pyi
@@ -0,0 +1,24 @@
+from typing import Union, Callable, Iterable
+
+from nonebot.typing import CommandName_T
+
+
+class CommandGroup:
+    """
+    Group a set of commands with same name prefix.
+    """
+
+    __slots__ = ('basename', 'base_kwargs')
+
+    def __init__(self, name: Union[str, CommandName_T], *,
+                 permission: int = ...,
+                 only_to_me: bool = ...,
+                 privileged: bool = ...,
+                 shell_like: bool = ...): ...
+
+    def command(self, name: Union[str, CommandName_T], *,
+                aliases: Iterable[str] = ...,
+                permission: int = ...,
+                only_to_me: bool = ...,
+                privileged: bool = ...,
+                shell_like: bool = ...) -> Callable: ...