diff --git a/delta_node/chain/identity/client.py b/delta_node/chain/identity/client.py
index bc1ad65..01009bb 100644
--- a/delta_node/chain/identity/client.py
+++ b/delta_node/chain/identity/client.py
@@ -32,7 +32,7 @@ async def update_name(self, address: str, name: str) -> str:
             _logger.error(e)
             raise
 
-    async def updaet_url(self, address: str, url: str) -> str:
+    async def update_url(self, address: str, url: str) -> str:
         req = pb.UpdateUrlReq(address=address, url=url)
         try:
             resp = await self.stub.UpdateUrl(req)
diff --git a/delta_node/main.py b/delta_node/main.py
index 02e9430..21805ea 100644
--- a/delta_node/main.py
+++ b/delta_node/main.py
@@ -24,18 +24,21 @@ async def _run():
     await db.init(config.db)
     chain.init(config.chain_host, config.chain_port, ssl=False)
     zk.init(config.zk_host, config.zk_port, ssl=False)
-    await registry.register(config.node_url, config.node_name)
-
+    r = registry.Registry(url=config.node_url, name=config.node_name)
+    await r.register()
+    
+    registry_fut = asyncio.create_task(r.start())
     runner_fut = asyncio.create_task(runner.run())
     app_fut = asyncio.create_task(app.run("0.0.0.0", config.api_port))
 
-    fut = asyncio.gather(runner_fut, app_fut)
+    fut = asyncio.gather(registry_fut, runner_fut, app_fut)
     loop.add_signal_handler(signal.SIGINT, lambda: fut.cancel())
     loop.add_signal_handler(signal.SIGTERM, lambda: fut.cancel())
     try:
         await fut
     finally:
-        await registry.unregister()
+        await r.stop()
+        await r.unregister()
         chain.close()
         zk.close()
         await db.close()
@@ -52,7 +55,7 @@ def run():
 
 
 async def _leave():
-    from delta_node import chain, config, db, log, pool, registry
+    from delta_node import chain, config, db, log, registry
 
     if len(config.chain_host) == 0:
         raise RuntimeError("chain connector host is required")
@@ -69,7 +72,10 @@ async def _leave():
 
     await db.init(config.db)
     chain.init(config.chain_host, config.chain_port, ssl=False)
-    await registry.unregister()
+
+    r = registry.Registry(url=config.node_url, name=config.node_name)
+    await r.unregister()
+
     chain.close()
     await db.close()
     listener.stop()
diff --git a/delta_node/registry/registry.py b/delta_node/registry/registry.py
index c5843f2..2e1b171 100644
--- a/delta_node/registry/registry.py
+++ b/delta_node/registry/registry.py
@@ -3,13 +3,13 @@
 from typing import Optional
 
 import sqlalchemy as sa
-from sqlalchemy.exc import NoResultFound
 from async_lru import alru_cache
 from delta_node import config, db
-from delta_node.entity.identity import Node
 from delta_node.chain import identity
+from delta_node.entity.identity import Node
+from sqlalchemy.exc import NoResultFound
 
-__all__ = ["register", "get_node_address", "unregister"]
+__all__ = ["get_node_address", "Registry"]
 
 
 _logger = logging.getLogger(__name__)
@@ -27,52 +27,77 @@ async def get_node_address() -> str:
             raise
 
 
-async def register(
-    url: str = config.node_url,
-    name: str = config.node_name,
-):
-    async with db.session_scope() as sess:
-        q = sa.select(Node).where(Node.id == 1)
-        node: Optional[Node] = (await sess.execute(q)).scalars().one_or_none()
-
-        if node:
-            # join first to avoid address changed when connect to monkey chain connector
-            _, address = await identity.get_client().join(url, name)
-            updated = False
-            if node.address != address:
-                node.address = address
-                updated = True
-            if node.url != url:
-                await identity.get_client().updaet_url(node.address, url)
-                node.url = url
-                updated = True
-            if node.name != name:
-                await identity.get_client().update_name(node.address, name)
-                node.name = name
-                updated = True
-            if updated:
+class Registry(object):
+    def __init__(
+        self, url: str = config.node_url, name: str = config.node_name
+    ) -> None:
+        self.url = url
+        self.name = name
+
+        self.running_task: Optional[asyncio.Task] = None
+
+    async def register(self):
+        _, address = await identity.get_client().join(self.url, self.name)
+
+        async with db.session_scope() as sess:
+            q = sa.select(Node).where(Node.id == 1)
+            node: Optional[Node] = (await sess.execute(q)).scalars().one_or_none()
+
+            if node is not None:
+                update = False
+                if node.address != address:
+                    node.address = address
+                    update = True
+                if node.url != self.url:
+                    node.url = self.url
+                    update = True
+                if node.name != self.name:
+                    node.name = self.name
+                    update = True
+                if update:
+                    sess.add(node)
+                    await sess.commit()
+                    _logger.info(f"register new node, node address: {address}")
+                else:
+                    _logger.info(f"registered node, node address: {address}")
+            else:
+                node = Node(url=self.url, name=self.name, address=address)
                 sess.add(node)
                 await sess.commit()
-            _logger.info(f"registered node, node address: {node.address}")
+                _logger.info(f"register new node, node address: {address}")
 
-        else:
-            _, address = await identity.get_client().join(url, name)
-            node = Node(url=url, name=name, address=address)
-            sess.add(node)
-            await sess.commit()
-            await sess.refresh(node)
-            _logger.info(f"register new node, node address: {node.address}")
+    async def unregister(self):
+        address = await get_node_address()
+        await identity.get_client().leave(address)
+
+        async with db.session_scope() as sess:
+            q = sa.select(Node).where(Node.id == 1)
+            node = (await sess.execute(q)).scalar_one()
 
+            await sess.delete(node)
+            await sess.commit()
 
-async def unregister():
-    address = await get_node_address()
-    await identity.get_client().leave(address)
+        _logger.info(f"node {address} leave")
 
-    async with db.session_scope() as sess:
-        q = sa.select(Node).where(Node.id == 1)
-        node = (await sess.execute(q)).scalar_one()
+    async def start(self, interval: int = 60):
+        async def run():
+            while True:
+                await asyncio.sleep(interval)
+                await identity.get_client().join(self.url, self.name)
 
-        await sess.delete(node)
-        await sess.commit()
+        if self.running_task is None:
+            self.running_task = asyncio.create_task(run())
+            try:
+                await self.running_task
+            except asyncio.CancelledError:
+                pass
+            except Exception as e:
+                _logger.exception(e)
+                raise
+        else:
+            raise ValueError("registry is already started")
 
-    _logger.info(f"node {address} leave")
+    async def stop(self):
+        if self.running_task is not None:
+            self.running_task.cancel()
+            _logger.info("stop registry")
diff --git a/delta_node/utils/precision.py b/delta_node/utils/precision.py
index fc007eb..775299f 100644
--- a/delta_node/utils/precision.py
+++ b/delta_node/utils/precision.py
@@ -3,13 +3,13 @@
 
 
 def fix_precision(arr: AggValueType, precision: int) -> AggValueType:
-    arr = arr.astype(np.float64)
-    arr = arr * (10**precision)
-    arr = arr.astype(np.int64)
-    return arr
+    _arr = arr.astype(np.float64)
+    _arr = _arr * (10**precision)
+    _arr = _arr.astype(np.int64)
+    return _arr
 
 
 def unfix_precision(arr: AggValueType, precision: int) -> AggValueType:
-    arr = arr.astype(np.float64)
-    arr = arr / (10**precision)
-    return arr
+    _arr = arr.astype(np.float64)
+    _arr = _arr / (10**precision)
+    return _arr
diff --git a/requirements.txt b/requirements.txt
index 1dad2e4..0dbf7e8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 aiosqlite==0.17.0
 async_lru==1.0.2
 cryptography==3.4.7
-delta-task==0.8.0
+delta-task==0.8.1
 fastapi==0.70.1
 grpclib==0.4.2
 httpx==0.23.0
diff --git a/setup.py b/setup.py
index 65dcb0a..adb25a7 100644
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,7 @@ def run_tests(self):
 
 setup(
     name="delta_node",
-    version="0.8.0",
+    version="0.8.1",
     packages=find_packages(),
     package_data={"delta_node": ["dataset/examples/*.csv"]},
     include_package_data=True,
@@ -39,7 +39,7 @@ def run_tests(self):
         "aiosqlite==0.17.0",
         "async_lru==1.0.2",
         "cryptography==3.4.7",
-        "delta-task==0.8.0",
+        "delta-task==0.8.1",
         "fastapi==0.70.1",
         "grpclib==0.4.2",
         "httpx==0.23.0",
diff --git a/tests/chain/identity_test.py b/tests/chain/identity_test.py
index fd8da65..70f3b0e 100644
--- a/tests/chain/identity_test.py
+++ b/tests/chain/identity_test.py
@@ -12,7 +12,7 @@ async def test_identity(identity_client: identity.Client):
     assert info.url == url
     # update url
     new_url = "http://127.0.0.1:6800"
-    await identity_client.updaet_url(address, new_url)
+    await identity_client.update_url(address, new_url)
     info = await identity_client.get_node_info(address)
     assert info.url == new_url
     url = new_url
diff --git a/tests/registry_test.py b/tests/registry_test.py
index 055e0f1..b853fc4 100644
--- a/tests/registry_test.py
+++ b/tests/registry_test.py
@@ -1,3 +1,4 @@
+import asyncio
 
 import pytest
 from delta_node import db, registry, chain
@@ -10,14 +11,24 @@ async def test_register():
     chain.init("127.0.0.1", 4500)
     url = "http://127.0.0.1:6800"
     name = "node1"
-    await registry.register(url, name)
+
+    r = registry.Registry(url, name)
+    await r.register()
+
+    fut = asyncio.create_task(r.start(interval=1))
+    
     address = await registry.get_node_address()
+    info = await identity.get_client().get_node_info(address)
+    assert info.address == address
+    assert info.name == name
+    assert info.url == url
 
-    node_info = await identity.get_client().get_node_info(address=address)
-    assert node_info.address == address
-    assert node_info.name == name
-    assert node_info.url == url
+    try:
+        await asyncio.wait_for(fut, timeout=2)
+    except asyncio.TimeoutError:
+        pass
 
-    await registry.unregister()
+    await r.stop()
+    await r.unregister()
     chain.close()
     await db.close()
\ No newline at end of file