diff --git a/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/ItemController.java b/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/ItemController.java
index afc15d89cff..e0c985b1035 100644
--- a/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/ItemController.java
+++ b/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/ItemController.java
@@ -195,7 +195,7 @@ public List<ItemDiffs> diff(@RequestBody NamespaceSyncModel model) {
   @PutMapping(value = "/apps/{appId}/namespaces/{namespaceName}/items", consumes = {"application/json"})
   public ResponseEntity<Void> update(@PathVariable String appId, @PathVariable String namespaceName,
                                      @RequestBody NamespaceSyncModel model) {
-    checkModel(!model.isInvalid());
+    checkModel(!model.isInvalid() && model.syncToNamespacesValid(appId, namespaceName));
     boolean hasPermission = permissionValidator.hasModifyNamespacePermission(appId, namespaceName);
     Env envNoPermission = null;
     // if uses has ModifyNamespace permission then he has permission
diff --git a/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/entity/model/NamespaceSyncModel.java b/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/entity/model/NamespaceSyncModel.java
index 85edd139feb..bac12fe818d 100644
--- a/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/entity/model/NamespaceSyncModel.java
+++ b/apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/entity/model/NamespaceSyncModel.java
@@ -41,6 +41,17 @@ public boolean isInvalid() {
     return false;
   }
 
+  public boolean syncToNamespacesValid(String appId, String namespaceName) {
+    for (NamespaceIdentifier namespaceIdentifier : syncToNamespaces) {
+      if (appId.equals(namespaceIdentifier.getAppId()) && namespaceName.equals(
+          namespaceIdentifier.getNamespaceName())) {
+        continue;
+      }
+      return false;
+    }
+    return true;
+  }
+
   public List<NamespaceIdentifier> getSyncToNamespaces() {
     return syncToNamespaces;
   }