diff --git a/heat/db/sqlalchemy/models.py b/heat/db/sqlalchemy/models.py
index a8fc5ff18ec..3639195890a 100644
--- a/heat/db/sqlalchemy/models.py
+++ b/heat/db/sqlalchemy/models.py
@@ -32,7 +32,7 @@
 BASE = declarative_base()
 
 
-class Json(types.TypeDecorator, types.MutableType):
+class Json(types.TypeDecorator):
     impl = types.Text
 
     def process_bind_param(self, value, dialect):
@@ -41,6 +41,15 @@ def process_bind_param(self, value, dialect):
     def process_result_value(self, value, dialect):
         return loads(value)
 
+# TODO(leizhang) When we removed sqlalchemy 0.7 dependence
+# we can import MutableDict directly and remove ./mutable.py
+try:
+    from sqlalchemy.ext.mutable import MutableDict as sa_MutableDict
+    sa_MutableDict.associate_with(Json)
+except ImportError:
+    from heat.db.sqlalchemy.mutable import MutableDict
+    MutableDict.associate_with(Json)
+
 
 class HeatBase(object):
     """Base class for Heat Models."""
diff --git a/heat/db/sqlalchemy/mutable.py b/heat/db/sqlalchemy/mutable.py
new file mode 100644
index 00000000000..040cc7d0723
--- /dev/null
+++ b/heat/db/sqlalchemy/mutable.py
@@ -0,0 +1,64 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+#
+#    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)