diff --git a/tools/check_i18n.py b/tools/check_i18n.py
new file mode 100644
index 000000000..43a4f9bc3
--- /dev/null
+++ b/tools/check_i18n.py
@@ -0,0 +1,154 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    Copyright 2012 OpenStack LLC
+#
+#    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.
+
+import compiler
+import imp
+import os.path
+import sys
+
+
+def is_localized(node):
+    """ Check message wrapped by _() """
+    if isinstance(node.parent, compiler.ast.CallFunc):
+        if isinstance(node.parent.node, compiler.ast.Name):
+            if node.parent.node.name == '_':
+                return True
+    return False
+
+
+class ASTWalker(compiler.visitor.ASTVisitor):
+
+    def default(self, node, *args):
+        for child in node.getChildNodes():
+            child.parent = node
+        compiler.visitor.ASTVisitor.default(self, node, *args)
+
+
+class Visitor(object):
+
+    def __init__(self, filename, i18n_msg_predicates,
+                 msg_format_checkers, debug):
+        self.filename = filename
+        self.debug = debug
+        self.error = 0
+        self.i18n_msg_predicates = i18n_msg_predicates
+        self.msg_format_checkers = msg_format_checkers
+        with open(filename) as f:
+            self.lines = f.readlines()
+
+    def visitConst(self, node):
+        if not isinstance(node.value, str):
+            return
+
+        if is_localized(node):
+            for (checker, msg) in self.msg_format_checkers:
+                if checker(node):
+                    print >> sys.stderr, (
+                        '%s:%d %s: %s' %
+                        (self.filename, node.lineno,
+                         self.lines[node.lineno - 1][:-1],
+                         "Error: %s" % msg))
+                    self.error = 1
+                    return
+            if debug:
+                print ('%s:%d %s: %s' %
+                       (self.filename, node.lineno,
+                        self.lines[node.lineno - 1][:-1],
+                        "Pass"))
+        else:
+            for (predicate, action, msg) in self.i18n_msg_predicates:
+                if predicate(node):
+                    if action == 'skip':
+                        if debug:
+                            print ('%s:%d %s: %s' %
+                                   (self.filename, node.lineno,
+                                    self.lines[node.lineno - 1][:-1],
+                                    "Pass"))
+                        return
+                    elif action == 'error':
+                        print >> sys.stderr, (
+                            '%s:%d %s: %s' %
+                            (self.filename, node.lineno,
+                             self.lines[node.lineno - 1][:-1],
+                             "Error: %s" % msg))
+                        self.error = 1
+                        return
+                    elif action == 'warn':
+                        print ('%s:%d %s: %s' %
+                               (self.filename, node.lineno,
+                                self.lines[node.lineno - 1][:-1],
+                                "Warn: %s" % msg))
+                        return
+                    print >> sys.stderr, 'Predicate with wrong action!'
+
+
+def is_file_in_black_list(black_list, f):
+    for f in black_list:
+        if os.path.abspath(input_file).startswith(
+            os.path.abspath(f)):
+            return True
+    return False
+
+
+def check_i18n(input_file, i18n_msg_predicates, msg_format_checkers, debug):
+    input_mod = compiler.parseFile(input_file)
+    v = compiler.visitor.walk(input_mod,
+                              Visitor(input_file,
+                                      i18n_msg_predicates,
+                                      msg_format_checkers,
+                                      debug),
+                              ASTWalker())
+    return v.error
+
+
+if __name__ == '__main__':
+    input_path = sys.argv[1]
+    cfg_path = sys.argv[2]
+    try:
+        cfg_mod = imp.load_source('', cfg_path)
+    except:
+        print >> sys.stderr, "Load cfg module failed"
+        sys.exit(1)
+
+    i18n_msg_predicates = cfg_mod.i18n_msg_predicates
+    msg_format_checkers = cfg_mod.msg_format_checkers
+    black_list = cfg_mod.file_black_list
+
+    debug = False
+    if len(sys.argv) > 3:
+        if sys.argv[3] == '-d':
+            debug = True
+
+    if os.path.isfile(input_path):
+        sys.exit(check_i18n(input_path,
+                            i18n_msg_predicates,
+                            msg_format_checkers,
+                            debug))
+
+    error = 0
+    for dirpath, dirs, files in os.walk(input_path):
+        for f in files:
+            if not f.endswith('.py'):
+                continue
+            input_file = os.path.join(dirpath, f)
+            if is_file_in_black_list(black_list, input_file):
+                continue
+            if check_i18n(input_file,
+                          i18n_msg_predicates,
+                          msg_format_checkers,
+                          debug):
+                error = 1
+    sys.exit(error)
diff --git a/tools/check_i18n_test_case.txt b/tools/check_i18n_test_case.txt
new file mode 100644
index 000000000..3d1391d94
--- /dev/null
+++ b/tools/check_i18n_test_case.txt
@@ -0,0 +1,67 @@
+# test-case for check_i18n.py
+# python check_i18n.py check_i18n.txt -d
+
+# message format checking
+#  capital checking
+msg = _("hello world, error")
+msg = _("hello world_var, error")
+msg = _('file_list xyz, pass')
+msg = _("Hello world, pass")
+
+#  format specifier checking
+msg = _("Hello %s world %d, error")
+msg = _("Hello %s world, pass")
+msg = _("Hello %(var1)s world %(var2)s, pass")
+
+# message has been localized
+#  is_localized
+msg = _("Hello world, pass")
+msg = _("Hello world, pass") % var
+LOG.debug(_('Hello world, pass'))
+LOG.info(_('Hello world, pass'))
+raise x.y.Exception(_('Hello world, pass'))
+raise Exception(_('Hello world, pass'))
+
+# message need be localized
+#  is_log_callfunc
+LOG.debug('hello world, error')
+LOG.debug('hello world, error' % xyz)
+sys.append('hello world, warn')
+
+# is_log_i18n_msg_with_mod
+LOG.debug(_('Hello world, error') % xyz)
+
+# default warn
+msg = 'hello world, warn'
+msg = 'hello world, warn' % var
+
+# message needn't be localized
+#  skip only one word
+msg = ''
+msg = "hello,pass"
+
+#  skip dict
+msg = {'hello world, pass': 1}
+
+#  skip list
+msg = ["hello world, pass"]
+
+#  skip subscript
+msg['hello world, pass']
+
+#  skip xml marker
+msg = "<test><t></t></test>, pass"
+
+#  skip sql statement
+msg = "SELECT * FROM xyz WHERE hello=1, pass"
+msg = "select * from xyz, pass"
+
+#  skip add statement
+msg = 'hello world' + e + 'world hello, pass'
+
+#  skip doc string
+"""
+Hello world, pass
+"""
+class Msg:
+    pass
diff --git a/tools/i18n_cfg.py b/tools/i18n_cfg.py
new file mode 100644
index 000000000..23894a938
--- /dev/null
+++ b/tools/i18n_cfg.py
@@ -0,0 +1,98 @@
+import compiler
+import re
+
+
+def is_log_callfunc(n):
+    """ LOG.xxx('hello %s' % xyz) and LOG('hello') """
+    if isinstance(n.parent, compiler.ast.Mod):
+        n = n.parent
+    if isinstance(n.parent, compiler.ast.CallFunc):
+        if isinstance(n.parent.node, compiler.ast.Getattr):
+            if isinstance(n.parent.node.getChildNodes()[0],
+                          compiler.ast.Name):
+                if n.parent.node.getChildNodes()[0].name == 'LOG':
+                    return True
+    return False
+
+
+def is_log_i18n_msg_with_mod(n):
+    """ LOG.xxx("Hello %s" % xyz) should be LOG.xxx("Hello %s", xyz) """
+    if not isinstance(n.parent.parent, compiler.ast.Mod):
+        return False
+    n = n.parent.parent
+    if isinstance(n.parent, compiler.ast.CallFunc):
+        if isinstance(n.parent.node, compiler.ast.Getattr):
+            if isinstance(n.parent.node.getChildNodes()[0],
+                          compiler.ast.Name):
+                if n.parent.node.getChildNodes()[0].name == 'LOG':
+                    return True
+    return False
+
+
+def is_wrong_i18n_format(n):
+    """ Check _('hello %s' % xyz) """
+    if isinstance(n.parent, compiler.ast.Mod):
+        n = n.parent
+    if isinstance(n.parent, compiler.ast.CallFunc):
+        if isinstance(n.parent.node, compiler.ast.Name):
+            if n.parent.node.name == '_':
+                return True
+    return False
+
+
+"""
+Used for check message need be localized or not.
+(predicate_func, action, message)
+"""
+i18n_msg_predicates = [
+    # Skip ['hello world', 1]
+    (lambda n: isinstance(n.parent, compiler.ast.List), 'skip', ''),
+    # Skip {'hellow world', 1}
+    (lambda n: isinstance(n.parent, compiler.ast.Dict), 'skip', ''),
+    # Skip msg['hello world']
+    (lambda n: isinstance(n.parent, compiler.ast.Subscript), 'skip', ''),
+    # Skip doc string
+    (lambda n: isinstance(n.parent, compiler.ast.Discard), 'skip', ''),
+    # Skip msg = "hello", in normal, message should more than one word
+    (lambda n: len(n.value.strip().split(' ')) <= 1, 'skip', ''),
+    # Skip msg = 'hello world' + vars + 'world hello'
+    (lambda n: isinstance(n.parent, compiler.ast.Add), 'skip', ''),
+    # Skip xml markers msg = "<test></test>"
+    (lambda n: len(re.compile("</.*>").findall(n.value)) > 0, 'skip', ''),
+    # Skip sql statement
+    (lambda n: len(
+        re.compile("^SELECT.*FROM", flags=re.I).findall(n.value)) > 0,
+     'skip', ''),
+    # LOG.xxx()
+    (is_log_callfunc, 'error', 'Message must be localized'),
+    # _('hello %s' % xyz) should be _('hello %s') % xyz
+    (is_wrong_i18n_format, 'error',
+     ("Message format was wrong, _('hello %s' % xyz) "
+      "should be _('hello %s') % xyz")),
+    # default
+    (lambda n: True, 'warn', 'Message might need localized')
+]
+
+
+"""
+Used for checking message format. (checker_func, message)
+"""
+msg_format_checkers = [
+    # If message contain more than on format specifier, it should use
+    # mapping key
+    (lambda n: len(re.compile("%[bcdeEfFgGnosxX]").findall(n.value)) > 1,
+     "The message shouldn't contain more than one format specifier"),
+    # Check capital
+    (lambda n: n.value.split(' ')[0].count('_') == 0 and
+     n.value[0].isalpha() and
+     n.value[0].islower(),
+     "First letter must be capital"),
+    (is_log_i18n_msg_with_mod,
+     'LOG.xxx("Hello %s" % xyz) should be LOG.xxx("Hello %s", xyz)')
+]
+
+
+file_black_list = ["./quantum/plugins/cisco/tests/unit",
+                   "./quantum/tests/unit",
+                   "./quantum/openstack",
+                   "./quantum/plugins/bigswitch/tests"]
diff --git a/tox.ini b/tox.ini
index 937470e0e..e3b17ecdb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,6 +25,9 @@ commands =
   pep8 --repeat --show-source --ignore=E125 --exclude=.venv,.tox,dist,doc,openstack,*egg .
   pep8 --repeat --show-source --ignore=E125 --filename=quantum* bin
 
+[testenv:i18n]
+commands = python ./tools/check_i18n.py ./quantum ./tools/i18n_cfg.py
+
 [testenv:cover]
 setenv = NOSE_WITH_COVERAGE=1