diff --git a/services/case_service.py b/services/case_service.py
index ac535efa9e7dfd5a04f46fdb105a118c8ca900d0..401159b7a017eff3930dd198e69ef6f56c3586d8 100644
--- a/services/case_service.py
+++ b/services/case_service.py
@@ -256,6 +256,9 @@ async def get_follow_module_tree(node_id):
         if result['parent'] not in module_tree:
             module_tree[result['parent']] = list()
         module_tree[result['parent']].append(result)
+    if len(module_tree) == 0:
+        root['children'] = []
+        return root, True
     __build_module_tree(module_tree[int(node_id)], module_tree)
     root['children'] = module_tree[int(node_id)]
     return root, True