diff --git a/pulsar/apps/data/channels.py b/pulsar/apps/data/channels.py
index f051f495..d9ce708d 100644
--- a/pulsar/apps/data/channels.py
+++ b/pulsar/apps/data/channels.py
@@ -77,7 +77,14 @@ def __init__(self, pubsub, namespace=None, status_channel=None,
         self._connection_error = False
         self.channels = OrderedDict()
         self.logger = logger or LOGGER
-        self.namespace = '%s_' % (namespace or DEFAULT_NAMESPACE).lower()
+        self.namespace = (
+            namespace or
+            pubsub.store.urlparams.get('namespace') or
+            DEFAULT_NAMESPACE
+        ).lower()
+        if not self.namespace.endswith('_'):
+            self.namespace = '%s_' % self.namespace
+        self.dns = pubsub.store.buildurl(namespace=self.namespace)
         self.status_channel = (status_channel or DEFAULT_CHANNEL).lower()
         self.status = StatusType.initialised
         self.pubsub = pubsub
@@ -89,7 +96,7 @@ def _loop(self):
         return self.pubsub._loop
 
     def __repr__(self):
-        return '%s/%s' % (self.pubsub.store.dns, self.prefixed('*'))
+        return self.dns
 
     __str__ = __repr__
 
diff --git a/pulsar/apps/data/store.py b/pulsar/apps/data/store.py
index f42db1a0..bcc2ed0a 100644
--- a/pulsar/apps/data/store.py
+++ b/pulsar/apps/data/store.py
@@ -73,7 +73,7 @@ def __init__(self, name, host, database=None,
         self._password = password
         self._urlparams = {}
         self._init(**kw)
-        self._dns = self._buildurl()
+        self._dns = self.buildurl()
 
     @property
     def name(self):
@@ -88,7 +88,7 @@ def database(self):
     @database.setter
     def database(self, value):
         self._database = value
-        self._dns = self._buildurl()
+        self._dns = self.buildurl()
 
     @property
     def encoding(self):
@@ -101,6 +101,11 @@ def dns(self):
         '''Domain name server'''
         return self._dns
 
+    @property
+    def urlparams(self):
+        """url parameters in dns query"""
+        return self._urlparams
+
     @classmethod
     def register(cls):
         pass
@@ -145,7 +150,7 @@ def _init(self, **kw):  # pragma    nocover
         '''Internal initialisation'''
         pass
 
-    def _buildurl(self, **kw):
+    def buildurl(self, **kw):
         pre = ''
         if self._user:
             if self._password:
@@ -160,8 +165,8 @@ def _buildurl(self, **kw):
             host = '%s:%s' % host
         host = '%s%s' % (pre, host)
         path = '/%s' % self._database if self._database else ''
-        kw.update(self._urlparams)
-        query = urlencode(kw)
+        self._urlparams.update(kw)
+        query = urlencode(self._urlparams)
         scheme = self._name
         if self._scheme:
             scheme = '%s+%s' % (self._scheme, scheme)
diff --git a/tests/stores/channels.py b/tests/stores/channels.py
index 467ec753..0bc26a7a 100644
--- a/tests/stores/channels.py
+++ b/tests/stores/channels.py
@@ -16,9 +16,17 @@ def __call__(self, *args, **kwargs):
 
 class ChannelsTests:
 
-    def channels(self):
-        return Channels(self.store.pubsub(protocol=Json()),
-                        namespace=self.namespace())
+    def channels(self, **kw):
+        return Channels(self.store.pubsub(protocol=Json()), **kw)
+
+    def test_channels_dns(self):
+        channels = self.channels()
+        self.assertEqual(channels.namespace, '%s_' % self.namespace())
+        channels = self.channels(namespace='foo')
+        self.assertEqual(channels.namespace, 'foo_')
+        channels = self.channels(namespace='foo_')
+        self.assertEqual(channels.namespace, 'foo_')
+        self.assertTrue(str(channels).endswith('?namespace=foo_'))
 
     async def test_channels(self):
         channels = self.channels()