diff --git a/PaddleCV/object_detection/configs/faster_rcnn_r50_2x.yml b/PaddleCV/object_detection/configs/faster_rcnn_r50_2x.yml
index fba2c338e67894a8df71f6f93076d1e45f401c94..5530cb091c7f142f82543c133601e48fd3710fa8 100644
--- a/PaddleCV/object_detection/configs/faster_rcnn_r50_2x.yml
+++ b/PaddleCV/object_detection/configs/faster_rcnn_r50_2x.yml
@@ -43,7 +43,7 @@ RPNHead:
   train_proposal:
     min_size: 0.0
     nms_thresh: 0.7
-    pre_nums_top_n: 12000
+    pre_nms_top_n: 12000
     post_nms_top_n: 2000
   test_proposal:
     min_size: 0.0
diff --git a/PaddleCV/object_detection/tools/eval.py b/PaddleCV/object_detection/tools/eval.py
index 99a0db5318653e4219f19d1c6bc2a72777b3a9a1..590c08bb2ecfbc1098191d805d92602ff023c4fb 100644
--- a/PaddleCV/object_detection/tools/eval.py
+++ b/PaddleCV/object_detection/tools/eval.py
@@ -51,7 +51,7 @@ def main():
     if cfg['use_gpu']:
         devices_num = fluid.core.get_cuda_device_count()
     else:
-        devices_num = os.environ.get('CPU_NUM', multiprocessing.cpu_count())
+        devices_num = int(os.environ.get('CPU_NUM', multiprocessing.cpu_count()))
 
     if 'eval_feed' not in cfg:
         eval_feed = create(main_arch + 'EvalFeed')
diff --git a/PaddleCV/object_detection/tools/train.py b/PaddleCV/object_detection/tools/train.py
index 7d3991833e988a1b7dcd0e1b9a5570313bd64201..20667020aabf9b8436b0241895433397dec73fa6 100644
--- a/PaddleCV/object_detection/tools/train.py
+++ b/PaddleCV/object_detection/tools/train.py
@@ -53,7 +53,7 @@ def main():
     if cfg['use_gpu']:
         devices_num = fluid.core.get_cuda_device_count()
     else:
-        devices_num = os.environ.get('CPU_NUM', multiprocessing.cpu_count())
+        devices_num = int(os.environ.get('CPU_NUM', multiprocessing.cpu_count()))
 
     if 'train_feed' not in cfg:
         train_feed = create(type(main_arch).__name__ + 'TrainFeed')