diff --git a/api/controllers/service_api/dataset/document.py b/api/controllers/service_api/dataset/document.py
index becfb81da1..ac1ea820a6 100644
--- a/api/controllers/service_api/dataset/document.py
+++ b/api/controllers/service_api/dataset/document.py
@@ -174,7 +174,7 @@ class DocumentAddByFileApi(DatasetApiResource):
 
         if not dataset:
             raise ValueError('Dataset is not exist.')
-        if not dataset.indexing_technique and not args['indexing_technique']:
+        if not dataset.indexing_technique and not args.get('indexing_technique'):
             raise ValueError('indexing_technique is required.')
 
         # save file info