diff --git a/paddle/fluid/API.spec b/paddle/fluid/API.spec
index fbeb488443498e8572bd3793b3be5794de2412cd..d5083ed1fb0325b308e4dc1f31148f19b2097c6c 100644
--- a/paddle/fluid/API.spec
+++ b/paddle/fluid/API.spec
@@ -360,7 +360,7 @@ paddle.fluid.layers.iou_similarity (ArgSpec(args=['x', 'y', 'name'], varargs=Non
 paddle.fluid.layers.box_coder (ArgSpec(args=['prior_box', 'prior_box_var', 'target_box', 'code_type', 'box_normalized', 'name', 'axis'], varargs=None, keywords=None, defaults=('encode_center_size', True, None, 0)), ('document', '032d0f4b7d8f6235ee5d91e473344f0e'))
 paddle.fluid.layers.polygon_box_transform (ArgSpec(args=['input', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', 'e308ce1661cb722b220a6f482f85b9e4'))
 paddle.fluid.layers.yolov3_loss (ArgSpec(args=['x', 'gt_box', 'gt_label', 'anchors', 'anchor_mask', 'class_num', 'ignore_thresh', 'downsample_ratio', 'gt_score', 'use_label_smooth', 'name'], varargs=None, keywords=None, defaults=(None, True, None)), ('document', 'eb62b1ff7cc981f3483a62321a491f2e'))
-paddle.fluid.layers.yolo_box (ArgSpec(args=['x', 'img_size', 'anchors', 'class_num', 'conf_thresh', 'downsample_ratio', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', 'f332fb8c5bb581bd1a6b5be450a99990'))
+paddle.fluid.layers.yolo_box (ArgSpec(args=['x', 'img_size', 'anchors', 'class_num', 'conf_thresh', 'downsample_ratio', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '11b463ae2ad4c797fb91b3ee9864c4b4'))
 paddle.fluid.layers.box_clip (ArgSpec(args=['input', 'im_info', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '04384378ff00a42ade8fabd52e27cbc5'))
 paddle.fluid.layers.multiclass_nms (ArgSpec(args=['bboxes', 'scores', 'score_threshold', 'nms_top_k', 'keep_top_k', 'nms_threshold', 'normalized', 'nms_eta', 'background_label', 'name'], varargs=None, keywords=None, defaults=(0.3, True, 1.0, 0, None)), ('document', 'ca7d1107b6c5d2d6d8221039a220fde0'))
 paddle.fluid.layers.retinanet_detection_output (ArgSpec(args=['bboxes', 'scores', 'anchors', 'im_info', 'score_threshold', 'nms_top_k', 'keep_top_k', 'nms_threshold', 'nms_eta'], varargs=None, keywords=None, defaults=(0.05, 1000, 100, 0.3, 1.0)), ('document', '078d28607ce261a0cba2b965a79f6bb8'))
diff --git a/python/paddle/fluid/layers/detection.py b/python/paddle/fluid/layers/detection.py
index 3e7ef139c1bfdb4710b244b0f29f1bcef327c2d6..d81f6a383ae1b90f2dbe26b6ec37339312a05b03 100644
--- a/python/paddle/fluid/layers/detection.py
+++ b/python/paddle/fluid/layers/detection.py
@@ -921,8 +921,9 @@ def yolo_box(x,
 
         import paddle.fluid as fluid
         x = fluid.layers.data(name='x', shape=[255, 13, 13], dtype='float32')
+        img_size = fluid.layers.data(name='img_size',shape=[2],dtype='int64')
         anchors = [10, 13, 16, 30, 33, 23]
-        loss = fluid.layers.yolo_box(x=x, img_size=608, class_num=80, anchors=anchors, 
+        loss = fluid.layers.yolo_box(x=x, img_size=img_size, class_num=80, anchors=anchors, 
                                         conf_thresh=0.01, downsample_ratio=32)
     """
     helper = LayerHelper('yolo_box', **locals())