diff --git a/dface/prepare_data/gen_Pnet_train_data.py b/dface/prepare_data/gen_Pnet_train_data.py
index e69255a..e9c8fb3 100644
--- a/dface/prepare_data/gen_Pnet_train_data.py
+++ b/dface/prepare_data/gen_Pnet_train_data.py
@@ -43,7 +43,7 @@ def gen_pnet_data(data_dir,anno_file,prefix):
     for annotation in annotations:
         annotation = annotation.strip().split(' ')
         im_path = os.path.join(prefix,annotation[0])
-        bbox = map(float, annotation[1:])
+        bbox = list(map(float, annotation[1:]))
         boxes = np.array(bbox, dtype=np.int32).reshape(-1, 4)
         img = cv2.imread(im_path)
         idx += 1