diff --git a/easy_rec/python/layers/fm.py b/easy_rec/python/layers/fm.py
index c638456a4..1929e00aa 100644
--- a/easy_rec/python/layers/fm.py
+++ b/easy_rec/python/layers/fm.py
@@ -19,8 +19,7 @@ def __init__(self, name='fm'):
 
   def __call__(self, fm_fea):
     with tf.name_scope(self._name):
-      fm_feas = tf.concat(fm_fea, axis=1)
-      fm_feas = tf.expand_dims(fm_feas, axis=1)
+      fm_feas = tf.stack(fm_fea, axis=1)
       sum_square = tf.square(tf.reduce_sum(fm_feas, 1))
       square_sum = tf.reduce_sum(tf.square(fm_feas), 1)
       y_v = 0.5 * tf.subtract(sum_square, square_sum)