diff --git a/python/paddle/fluid/layers/detection.py b/python/paddle/fluid/layers/detection.py
index e0725242b7b28f92a9d788a17ec2fe84fcdacc83..63bac68e74759b266b5138b646f6a1aab7a51647 100644
--- a/python/paddle/fluid/layers/detection.py
+++ b/python/paddle/fluid/layers/detection.py
@@ -993,7 +993,7 @@ def yolov3_loss(x,
         "GTBox": gt_box,
         "GTLabel": gt_label,
     }
-    if gt_score:
+    if gt_score is not None:
         inputs["GTScore"] = gt_score
 
     attrs = {