diff --git a/qingcloud/app/connection.py b/qingcloud/app/connection.py
index 6135a75..7914f70 100644
--- a/qingcloud/app/connection.py
+++ b/qingcloud/app/connection.py
@@ -1,7 +1,6 @@
 from qingcloud.iaas.connection import APIConnection
 from qingcloud.conn import auth
 from . import constants as const
-from __builtin__ import str
 
 
 class AppConnection(APIConnection):