diff --git a/tensorlayer/utils.py b/tensorlayer/utils.py
index f1d171322..0dbdbdc12 100644
--- a/tensorlayer/utils.py
+++ b/tensorlayer/utils.py
@@ -130,15 +130,15 @@ def fit(sess, network, train_op, cost, X_train, y_train, x, y_, acc=None, batch_
                     result = sess.run(merged, feed_dict=feed_dict)
                     train_writer.add_summary(result, tensorboard_train_index)
                     tensorboard_train_index += 1
-
-                for X_val_a, y_val_a in iterate.minibatches(
+                if (X_val is not None) and (y_val is not None):                      
+                        for X_val_a, y_val_a in iterate.minibatches(
                                         X_val, y_val, batch_size, shuffle=True):
-                    dp_dict = dict_to_one( network.all_drop )    # disable noise layers
-                    feed_dict = {x: X_val_a, y_: y_val_a}
-                    feed_dict.update(dp_dict)
-                    result = sess.run(merged, feed_dict=feed_dict)
-                    val_writer.add_summary(result, tensorboard_val_index)
-                    tensorboard_val_index += 1
+                                dp_dict = dict_to_one( network.all_drop )    # disable noise layers
+                                feed_dict = {x: X_val_a, y_: y_val_a}
+                                feed_dict.update(dp_dict)
+                                result = sess.run(merged, feed_dict=feed_dict)
+                                val_writer.add_summary(result, tensorboard_val_index)
+                                tensorboard_val_index += 1
 
         if epoch + 1 == 1 or (epoch + 1) % print_freq == 0:
             if (X_val is not None) and (y_val is not None):