diff --git a/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java b/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java
index 9e012254329..d7db54e96c7 100644
--- a/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java
+++ b/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java
@@ -414,6 +414,10 @@ public String getNamespace() {
             return namespace;
         }
 
+        if (StringUtils.isNotEmpty(namespaceV2)) {
+            return namespaceV2;
+        }
+
         if (StringUtils.isNotEmpty(this.namesrvAddr)) {
             if (NameServerAddressUtils.validateInstanceEndpoint(namesrvAddr)) {
                 namespace = NameServerAddressUtils.parseInstanceIdFromEndpoint(namesrvAddr);
diff --git a/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java b/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java
index 5afe9cc011d..89bcf7a7d38 100644
--- a/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java
+++ b/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java
@@ -65,6 +65,38 @@ public void testQueuesWithNamespace() {
         assertEquals("lmq%defaultTopic", messageQueues.iterator().next().getTopic());
     }
 
+    @Test
+    public void testGetNamespaceFallbackToNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespaceV2("InstanceTest");
+        assertEquals("InstanceTest", config.getNamespace());
+    }
+
+    @Test
+    public void testWithNamespaceUsesNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespaceV2("InstanceTest");
+        assertEquals("InstanceTest%resource", config.withNamespace(resource));
+        assertEquals("InstanceTest%resource",
+            config.withNamespace("InstanceTest%resource"));
+    }
+
+    @Test
+    public void testWithoutNamespaceUsesNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespaceV2("InstanceTest");
+        assertEquals(resource, config.withoutNamespace("InstanceTest%resource"));
+    }
+
+    @Test
+    public void testNamespaceV1PrecedesNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespace("lmq");
+        config.setNamespaceV2("InstanceTest");
+        assertEquals("lmq", config.getNamespace());
+        assertEquals("lmq%resource", config.withNamespace(resource));
+    }
+
     private ClientConfig createClientConfig() {
         ClientConfig result = new ClientConfig();
         result.setUnitName("unitName");