diff --git a/apps/application/flow/step_node/image_understand_step_node/impl/base_image_understand_node.py b/apps/application/flow/step_node/image_understand_step_node/impl/base_image_understand_node.py
index 2ae04fb9893..4c7b670069f 100644
--- a/apps/application/flow/step_node/image_understand_step_node/impl/base_image_understand_node.py
+++ b/apps/application/flow/step_node/image_understand_step_node/impl/base_image_understand_node.py
@@ -256,7 +256,7 @@ def generate_history_human_message(self, chat_record):
                         *[{'type': 'image_url',
                            'image_url': {'url': f'data:image/{base64_image[1]};base64,{base64_image[0]}'}} for
                           base64_image in image_base64_list],
-                        *[{'type': 'image_url', 'image_url': url} for url in url_list]
+                        *[{'type': 'image_url', 'image_url': {'url': url}} for url in url_list]
                     ])
         return HumanMessage(content=chat_record.problem_text)