diff --git a/shadowsocks/tcprelay.py b/shadowsocks/tcprelay.py
index 38d4101..2eab8e4 100644
--- a/shadowsocks/tcprelay.py
+++ b/shadowsocks/tcprelay.py
@@ -707,3 +707,4 @@ class TCPRelay(object):
                 self._eventloop.remove_periodic(self.handle_periodic)
                 self._eventloop.remove(self._server_socket, self)
             self._server_socket.close()
+            self._server_socket = None