diff --git a/ppocr/data/det/db_process.py b/ppocr/data/det/db_process.py
index 71756516..41aca6cd 100644
--- a/ppocr/data/det/db_process.py
+++ b/ppocr/data/det/db_process.py
@@ -28,14 +28,22 @@ from .make_border_map import MakeBorderMap
 
 class DBProcessTrain(object):
     """
-    DB pre-process for Train mode
+    The pre-process of DB for train mode
     """
 
     def __init__(self, params):
+        """
+        :param params: dict of params
+        """
         self.img_set_dir = params['img_set_dir']
         self.image_shape = params['image_shape']
 
     def order_points_clockwise(self, pts):
+        """
+        Sort the points in the box clockwise
+        :param pts: points with shape [4, 2]
+        :return: sorted points
+        """
         rect = np.zeros((4, 2), dtype="float32")
         s = pts.sum(axis=1)
         rect[0] = pts[np.argmin(s)]
@@ -46,6 +54,12 @@ class DBProcessTrain(object):
         return rect
 
     def make_data_dict(self, imgvalue, entry):
+        """
+        create input dict
+        :param imgvalue: input image
+        :param entry: dict of annotations information
+        :return: created dict of input data information
+        """
         boxes = []
         texts = []
         ignores = []
@@ -71,6 +85,11 @@ class DBProcessTrain(object):
         return data
 
     def NormalizeImage(self, data):
+        """
+        Normalize input image
+        :param data: input dict
+        :return: new dict with normalized image
+        """
         im = data['image']
         img_mean = [0.485, 0.456, 0.406]
         img_std = [0.229, 0.224, 0.225]
@@ -84,6 +103,11 @@ class DBProcessTrain(object):
         return data
 
     def FilterKeys(self, data):
+        """
+        Filter keys
+        :param data: dict
+        :return:
+        """
         filter_keys = ['polys', 'texts', 'ignore_tags', 'shape']
         for key in filter_keys:
             if key in data:
@@ -91,6 +115,11 @@ class DBProcessTrain(object):
         return data
 
     def convert_label_infor(self, label_infor):
+        """
+        encode annotations using json.loads
+        :param label_infor: string
+        :return: (image, encoded annotations)
+        """
         label_infor = label_infor.decode()
         label_infor = label_infor.encode('utf-8').decode('utf-8-sig')
         substr = label_infor.strip("\n").split("\t")
@@ -184,6 +213,11 @@ class DBProcessTest(object):
         return im, (ratio_h, ratio_w)
 
     def resize_image_type1(self, im):
+        """
+        resize image to a size self.image_shape
+        :param im: input image
+        :return: normalized image and resize ratio
+        """
         resize_h, resize_w = self.image_shape
         ori_h, ori_w = im.shape[:2]  # (h, w, c)
         im = cv2.resize(im, (int(resize_w), int(resize_h)))
@@ -192,6 +226,11 @@ class DBProcessTest(object):
         return im, (ratio_h, ratio_w)
 
     def normalize(self, im):
+        """
+        Normalize image
+        :param im: input image
+        :return: Normalized image
+        """
         img_mean = [0.485, 0.456, 0.406]
         img_std = [0.229, 0.224, 0.225]
         im = im.astype(np.float32, copy=False)