diff --git a/tools/accnn/acc_conv.py b/tools/accnn/acc_conv.py
index 8f468def14fc..095e386beebc 100644
--- a/tools/accnn/acc_conv.py
+++ b/tools/accnn/acc_conv.py
@@ -67,11 +67,11 @@ def main():
 if __name__ == '__main__':
   parser=argparse.ArgumentParser()
   parser.add_argument('-m', '--model', help='the model to speed up')
-  parser.add_argument('-g', '--gpus', default='0,1,2,3', help='the gpus to be used in ctx')
+  parser.add_argument('-g', '--gpus', default='0', help='the gpus to be used in ctx')
   parser.add_argument('--load-epoch',type=int,default=1)
   parser.add_argument('--layer')
   parser.add_argument('--K', type=int)
   parser.add_argument('--save-model')
   args = parser.parse_args()
   main()
-  
\ No newline at end of file
+  
diff --git a/tools/accnn/acc_fc.py b/tools/accnn/acc_fc.py
index a7b7da163990..dcc255452b1d 100644
--- a/tools/accnn/acc_fc.py
+++ b/tools/accnn/acc_fc.py
@@ -48,7 +48,7 @@ def main():
 if __name__ == '__main__':
   parser=argparse.ArgumentParser()
   parser.add_argument('-m', '--model', help='the model to speed up')
-  parser.add_argument('-g', '--gpus', default='0,1,2,3', help='the gpus to be used in ctx')
+  parser.add_argument('-g', '--gpus', default='0', help='the gpus to be used in ctx')
   parser.add_argument('--load-epoch',type=int,default=1)
   parser.add_argument('--layer')
   parser.add_argument('--K', type=int)