diff --git a/senlin/db/sqlalchemy/mutable.py b/senlin/db/sqlalchemy/mutable.py
deleted file mode 100644
index 3b12184e1..000000000
--- a/senlin/db/sqlalchemy/mutable.py
+++ /dev/null
@@ -1,62 +0,0 @@
-# Licensed under the Apache License, Version 2.0 (the "License"); you may
-# not use this file except in compliance with the License. You may obtain
-# a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-# License for the specific language governing permissions and limitations
-# under the License.
-#
-# The MIT License
-#
-# ext/mutable.py
-# Copyright (C) 2005-2013 the SQLAlchemy authors
-# and contributors <see AUTHORS file>
-#
-# This module is part of SQLAlchemy and is released under
-# the MIT License: http://www.opensource.org/lic enses/mit-license.php
-"""
-Submitted on behalf of a third-party: sqlalchemy
-"""
-from sqlalchemy.ext.mutable import Mutable
-
-
-class MutableDict(Mutable, dict):
-    """A dictionary type that implements :class:`.Mutable`.
-
-    .. versionadded:: 0.8
-
-    """
-
-    def __setitem__(self, key, value):
-        """Detect dictionary set events and emit change events."""
-        dict.__setitem__(self, key, value)
-        self.changed()
-
-    def __delitem__(self, key):
-        """Detect dictionary del events and emit change events."""
-        dict.__delitem__(self, key)
-        self.changed()
-
-    def clear(self):
-        dict.clear(self)
-        self.changed()
-
-    @classmethod
-    def coerce(cls, key, value):
-        """Convert plain dictionary to MutableDict."""
-        if not isinstance(value, MutableDict):
-            if isinstance(value, dict):
-                return MutableDict(value)
-            return Mutable.coerce(key, value)
-        else:
-            return value
-
-    def __getstate__(self):
-        return dict(self)
-
-    def __setstate__(self, state):
-        self.update(state)
diff --git a/senlin/db/sqlalchemy/types.py b/senlin/db/sqlalchemy/types.py
index 95ebd280e..e118c2be6 100644
--- a/senlin/db/sqlalchemy/types.py
+++ b/senlin/db/sqlalchemy/types.py
@@ -14,9 +14,9 @@
 import json
 
 from sqlalchemy.dialects import mysql
+from sqlalchemy.ext import mutable
 from sqlalchemy import types
 
-
 dumps = json.dumps
 loads = json.loads
 
@@ -32,7 +32,6 @@ class LongText(types.TypeDecorator):
 
 
 class Json(LongText):
-
     def process_bind_param(self, value, dialect):
         return dumps(value)
 
@@ -42,15 +41,5 @@ class Json(LongText):
         return loads(value)
 
 
-def associate_with(sqltype):
-    # TODO(leizhang) When we removed sqlalchemy 0.7 dependence
-    # we can import MutableDict directly and remove ./mutable.py
-    try:
-        from sqlalchemy.ext import mutable
-        mutable.MutableDict.associate_with(Json)
-    except ImportError:
-        from senlin.db.sqlalchemy import mutable
-        mutable.MutableDict.associate_with(Json)
-
-associate_with(LongText)
-associate_with(Json)
+mutable.MutableDict.associate_with(LongText)
+mutable.MutableDict.associate_with(Json)