diff --git a/tensorlayer/files.py b/tensorlayer/files.py
index 0e9253baa..7b9568a7d 100644
--- a/tensorlayer/files.py
+++ b/tensorlayer/files.py
@@ -646,14 +646,14 @@ def save_npz(save_list=[], name='model.npz', sess=None):
     """
     ## save params into a list
     save_list_var = []
-    for k, value in enumerate(save_list):
-        if sess:
-            save_list_var.append( sess.run(value) )
-        else:
-            try:
-                save_list_var.append( value.eval() )
-            except:
-                print(" Fail to save model, Hint: pass the session into this function, save_npz(network.all_params, name='model.npz', sess=sess)")
+    if sess:
+        save_list_var = sess.run(save_list)
+    else:
+        try:
+            for k, value in enumerate(save_list):
+                save_list_var.append(value.eval())
+        except:
+            print(" Fail to save model, Hint: pass the session into this function, save_npz(network.all_params, name='model.npz', sess=sess)")
     np.savez(name, params=save_list_var)
     save_list_var = None
     del save_list_var
@@ -734,9 +734,10 @@ def assign_params(sess, params, network):
     ----------
     - `Assign value to a TensorFlow variable <http://stackoverflow.com/questions/34220532/how-to-assign-value-to-a-tensorflow-variable>`_
     """
+    ops = []
     for idx, param in enumerate(params):
-        assign_op = network.all_params[idx].assign(param)
-        sess.run(assign_op)
+        ops.append(network.all_params[idx].assign(param))
+    sess.run(ops)