diff --git a/tensorlayer/layers/core.py b/tensorlayer/layers/core.py
index 799a9d4bd..73b7f1919 100644
--- a/tensorlayer/layers/core.py
+++ b/tensorlayer/layers/core.py
@@ -862,7 +862,7 @@ def __init__(
             sentence_lengths = tf.count_nonzero(
                 masks,
                 axis=1,
-                keep_dims=True,
+                keepdims=True,
                 # dtype=tf.float32,
                 dtype=LayersConfig.tf_dtype,
                 name='sentence_lengths',