diff --git a/fastapi_amis_admin/globals/__init__.py b/fastapi_amis_admin/globals/__init__.py
new file mode 100644
index 0000000..c8c38e2
--- /dev/null
+++ b/fastapi_amis_admin/globals/__init__.py
@@ -0,0 +1,2 @@
+from .db import async_db, sync_db
+from .sites import site
diff --git a/fastapi_amis_admin/globals/db.py b/fastapi_amis_admin/globals/db.py
new file mode 100644
index 0000000..2992310
--- /dev/null
+++ b/fastapi_amis_admin/globals/db.py
@@ -0,0 +1,77 @@
+from collections import namedtuple
+from typing import Dict, Union
+
+from lazy_object_proxy import Proxy
+from sqlalchemy_database import AsyncDatabase, Database
+from typing_extensions import overload
+
+from fastapi_amis_admin.globals.sites import exists_site, get_site
+
+DBs = namedtuple("DBs", ["sync", "async_"])
+
+__dbs__: Dict[str, DBs] = {}
+
+
+@overload
+def get_db(alias: str = "default") -> Database:
+    ...
+
+
+@overload
+def get_db(alias: str = "default", is_async: bool = True) -> AsyncDatabase:
+    ...
+
+
+def get_async_db(alias: str = "default") -> AsyncDatabase:
+    """获取异步数据库"""
+    return get_db(alias, is_async=True)
+
+
+def get_db(alias: str = "default", is_async: bool = False) -> Union[Database, AsyncDatabase]:
+    """获取数据库"""
+    if alias in __dbs__:
+        dbs = __dbs__[alias]
+        if is_async and dbs.async_:
+            return dbs.async_
+        elif not is_async and dbs.sync:
+            return dbs.sync
+    if exists_site(alias):
+        db = get_site(alias).db
+        if is_async and isinstance(db, AsyncDatabase):
+            return db
+        elif not is_async and isinstance(db, Database):
+            return db
+    raise ValueError(f"db[{alias}] not found, please call `set_db` first")
+
+
+def set_db(db: Union[Database, AsyncDatabase], alias: str = "default") -> None:
+    """设置数据库"""
+    if alias not in __dbs__:
+        __dbs__[alias] = DBs(sync=None, async_=None)
+    if isinstance(db, AsyncDatabase):
+        if __dbs__[alias].async_ is not None:
+            raise ValueError(f"async db[{alias}] already exists")
+        __dbs__[alias] = __dbs__[alias]._replace(async_=db)
+    elif isinstance(db, Database):
+        if __dbs__[alias].sync is not None:
+            raise ValueError(f"sync db[{alias}] already exists")
+        __dbs__[alias] = __dbs__[alias]._replace(sync=db)
+    else:
+        raise ValueError(f"db[{alias}] must be Database or AsyncDatabase")
+
+
+def exists_db(alias: str = "default", is_async: bool = False) -> bool:
+    """判断数据库是否存在"""
+    if alias in __dbs__:
+        dbs = __dbs__[alias]
+        if is_async and dbs.async_:
+            return True
+        elif not is_async and dbs.sync:
+            return True
+    return False
+
+
+# 默认同步数据库.需要在项目启动时调用`set_db`设置
+sync_db: Database = Proxy(get_db)
+# 默认异步数据库.需要在项目启动时调用`set_db`设置
+async_db: AsyncDatabase = Proxy(get_async_db)
diff --git a/fastapi_amis_admin/globals/deps.py b/fastapi_amis_admin/globals/deps.py
new file mode 100644
index 0000000..8064879
--- /dev/null
+++ b/fastapi_amis_admin/globals/deps.py
@@ -0,0 +1,9 @@
+from fastapi import Depends
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import Session
+from typing_extensions import Annotated
+
+from fastapi_amis_admin.globals.db import async_db, sync_db
+
+SyncSess = Annotated[Session, Depends(sync_db.session_generator)]
+AsyncSess = Annotated[AsyncSession, Depends(async_db.session_generator)]
diff --git a/fastapi_amis_admin/globals/sites.py b/fastapi_amis_admin/globals/sites.py
new file mode 100644
index 0000000..1706b84
--- /dev/null
+++ b/fastapi_amis_admin/globals/sites.py
@@ -0,0 +1,30 @@
+from typing import Dict
+
+from lazy_object_proxy import Proxy
+
+from fastapi_amis_admin.admin import AdminSite
+
+__sites__: Dict[str, AdminSite] = {}
+
+
+def get_site(alias: str = "default") -> AdminSite:
+    """获取站点"""
+    if alias not in __sites__:
+        raise ValueError(f"site[{alias}] not found, please call `set_site` first")
+    return __sites__[alias]
+
+
+def set_site(site: AdminSite, alias: str = "default") -> None:
+    """设置站点"""
+    if alias in __sites__:
+        raise ValueError(f"site[{alias}] already exists")
+    __sites__[alias] = site
+
+
+def exists_site(alias: str = "default") -> bool:
+    """判断站点是否存在"""
+    return alias in __sites__
+
+
+# 默认站点.需要在项目启动时调用`set_site`设置
+site: AdminSite = Proxy(get_site)
diff --git a/pyproject.toml b/pyproject.toml
index 346e8c7..d39feaf 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -42,6 +42,7 @@ dependencies = [
     "python-multipart>=0.0.5",
     "sqlalchemy-database>=0.1.0,<0.2.0",
     "aiofiles>=0.17.0",
+    "lazy-object-proxy>=1.9.0",
 ]
 
 
diff --git a/tests/test_globals/__init__.py b/tests/test_globals/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_globals/test_db.py b/tests/test_globals/test_db.py
new file mode 100644
index 0000000..2c8b885
--- /dev/null
+++ b/tests/test_globals/test_db.py
@@ -0,0 +1,38 @@
+import pytest
+
+from fastapi_amis_admin.globals import db, sites
+from tests.conftest import sync_db
+
+
+def test_sites(site):
+    # 清空sites,db,确保测试环境
+    sites.__sites__.clear()
+    db.__dbs__.clear()
+    # 没有设置db,返回False
+    assert db.exists_db() is False
+    assert db.exists_db(is_async=True) is False
+    with pytest.raises(ValueError):
+        assert db.sync_db
+    with pytest.raises(ValueError):
+        assert db.async_db
+    # 设置site,site.db为异步数据库
+    sites.set_site(site)
+    # 判断db是否存在
+    assert db.exists_db() is False
+    assert db.exists_db(is_async=True) is False
+    # 获取db
+    with pytest.raises(ValueError):
+        assert db.sync_db
+    assert db.async_db == site.db  # 读取site.db
+    assert isinstance(db.async_db, db.AsyncDatabase)
+    # 设置同步db
+    db.set_db(sync_db)
+    # 判断db是否存在
+    assert db.exists_db() is True
+    assert db.exists_db(is_async=True) is False
+    # 获取db
+    assert db.sync_db == sync_db
+    assert isinstance(db.sync_db, db.Database)
+    # 重复设置db
+    with pytest.raises(ValueError):
+        db.set_db(sync_db)
diff --git a/tests/test_globals/test_sites.py b/tests/test_globals/test_sites.py
new file mode 100644
index 0000000..3cb996f
--- /dev/null
+++ b/tests/test_globals/test_sites.py
@@ -0,0 +1,26 @@
+import pytest
+
+from fastapi_amis_admin.globals import sites
+
+
+def test_sites(site):
+    # 清空sites,确保测试环境
+    sites.__sites__.clear()
+    # 没有设置站点,返回False
+    assert sites.exists_site() is False
+    # 没有设置站点,抛出异常
+    with pytest.raises(ValueError):
+        assert sites.get_site()
+    with pytest.raises(ValueError):
+        assert sites.site
+    # 设置站点
+    sites.set_site(site)
+    # 判断站点是否存在
+    assert sites.exists_site() is True
+    # 获取站点
+    assert sites.get_site() == site
+    assert sites.site == site
+    assert isinstance(sites.site, sites.AdminSite)
+    # 重复设置站点
+    with pytest.raises(ValueError):
+        sites.set_site(site)