diff --git a/mmdet3d/utils/setup_env.py b/mmdet3d/utils/setup_env.py
index 282ad491e7..98bcc8853f 100644
--- a/mmdet3d/utils/setup_env.py
+++ b/mmdet3d/utils/setup_env.py
@@ -1,8 +1,9 @@
 # Copyright (c) OpenMMLab. All rights reserved.
-import cv2
 import os
 import platform
 import warnings
+
+import cv2
 from torch import multiprocessing as mp
 
 
diff --git a/tests/test_utils/test_setup_env.py b/tests/test_utils/test_setup_env.py
index 08233efa71..0c070c9f0e 100644
--- a/tests/test_utils/test_setup_env.py
+++ b/tests/test_utils/test_setup_env.py
@@ -1,8 +1,9 @@
 # Copyright (c) OpenMMLab. All rights reserved.
-import cv2
 import multiprocessing as mp
 import os
 import platform
+
+import cv2
 from mmcv import Config
 
 from mmdet3d.utils import setup_multi_processes
diff --git a/tools/data_converter/kitti_data_utils.py b/tools/data_converter/kitti_data_utils.py
index 206d50d680..8e3dba6f35 100644
--- a/tools/data_converter/kitti_data_utils.py
+++ b/tools/data_converter/kitti_data_utils.py
@@ -4,6 +4,7 @@
 from os import path as osp
 from pathlib import Path
 
+import mmcv
 import numpy as np
 from skimage import io