diff --git a/python/paddle/fluid/layers/detection.py b/python/paddle/fluid/layers/detection.py
index e984576ffe8ce9549925b23ee79b24b9b7773d0a..febfc8e127e570ae1a94fd09f72f24315023d280 100644
--- a/python/paddle/fluid/layers/detection.py
+++ b/python/paddle/fluid/layers/detection.py
@@ -482,7 +482,7 @@ def yolov3_loss(x,
         raise TypeError("Attr anchor_mask of yolov3_loss must be list or tuple")
     if not isinstance(class_num, int):
         raise TypeError("Attr class_num of yolov3_loss must be an integer")
-    if not isinstance(class_num, int):
+    if not isinstance(use_label_smooth, int):
         raise TypeError("Attr ues_label_smooth of yolov3 must be a bool value")
     if not isinstance(ignore_thresh, float):
         raise TypeError(
diff --git a/python/paddle/fluid/tests/unittests/test_yolov3_loss_op.py b/python/paddle/fluid/tests/unittests/test_yolov3_loss_op.py
index 1746a1da1dc48b322e8266861036751751199586..79c953bbd1fcf5d3ae2f49fcd15a332a71d4dcba 100644
--- a/python/paddle/fluid/tests/unittests/test_yolov3_loss_op.py
+++ b/python/paddle/fluid/tests/unittests/test_yolov3_loss_op.py
@@ -76,7 +76,7 @@ def YOLOv3Loss(x, gtbox, gtlabel, gtscore, attrs):
     class_num = attrs["class_num"]
     ignore_thresh = attrs['ignore_thresh']
     downsample = attrs['downsample']
-    #use_label_smooth = attrs['use_label_smooth']
+    use_label_smooth = attrs['use_label_smooth']
     input_size = downsample * h
     x = x.reshape((n, mask_num, 5 + class_num, h, w)).transpose((0, 1, 3, 4, 2))
     loss = np.zeros((n)).astype('float32')