diff --git a/tools/infer/infer.py b/tools/infer/infer.py
index 9a3b8fff9..b06a51bd5 100644
--- a/tools/infer/infer.py
+++ b/tools/infer/infer.py
@@ -105,6 +105,7 @@ def main():
     exe, program, feed_names, fetch_names = create_predictor(args)
 
     data = preprocess(args.image_file, operators)
+    data = np.expand_dims(data, axis=0)
     outputs = exe.run(program,
                       feed={feed_names[0]: data},
                       fetch_list=fetch_names,