diff --git a/deploy/cpp/include/paddlex/transforms.h b/deploy/cpp/include/paddlex/transforms.h
index 43ecd0352d2474aed9f8ffa45dc6d4ce6f93d651..66e9839a92c406c30139eec8ef96a877ddcaaa83 100644
--- a/deploy/cpp/include/paddlex/transforms.h
+++ b/deploy/cpp/include/paddlex/transforms.h
@@ -28,7 +28,10 @@
 
 namespace PaddleX {
 
-// Object for storing all preprocessed data
+/*
+ * @brief
+ * This class represents object for storing all preprocessed data
+ * */
 class ImageBlob {
  public:
   // Original image height and width
@@ -51,13 +54,28 @@ class ImageBlob {
   }
 };
 
-// Abstraction of preprocessing opration class
+/*
+ * @brief
+ * Abstraction of preprocessing operation class
+ * */
 class Transform {
  public:
   virtual void Init(const YAML::Node& item) = 0;
+  /*
+   * @brief
+   * This method executes preprocessing operation on image matrix,
+   * result will be returned at second parameter.
+   * @param im: single image matrix to be preprocessed
+   * @param data: the raw data of single image matrix after preprocessed 
+   * @return true if transform successfully
+   * */
   virtual bool Run(cv::Mat* im, ImageBlob* data) = 0;
 };
 
+/*
+ * @brief
+ * This class execute normalization operation on image matrix
+ * */
 class Normalize : public Transform {
  public:
   virtual void Init(const YAML::Node& item) {
@@ -72,6 +90,14 @@ class Normalize : public Transform {
   std::vector<float> std_;
 };
 
+/*
+ * @brief
+ * This class execute resize by short operation on image matrix. At first, it resizes 
+ * the short side of image matrix to specified length. Accordingly, the long side
+ * will be resized in the same proportion. If new length of long side exceeds max
+ * size, the long size will be resized to max size, and the short size will be 
+ * resized in the same proportion
+ * */
 class ResizeByShort : public Transform {
  public:
   virtual void Init(const YAML::Node& item) {
@@ -90,6 +116,12 @@ class ResizeByShort : public Transform {
   int max_size_;
 };
 
+/*
+ * @brief
+ * This class execute resize by long operation on image matrix. At first, it resizes
+ * the long side of image matrix to specified length. Accordingly, the short side
+ * will be resized in the same proportion.
+ * */
 class ResizeByLong : public Transform {
  public:
   virtual void Init(const YAML::Node& item) {
@@ -101,6 +133,11 @@ class ResizeByLong : public Transform {
   int long_size_;
 };
 
+/*
+ * @brief
+ * This class execute resize operation on image matrix. It resizes width and height
+ * to specified length.
+ * */
 class Resize : public Transform {
  public:
   virtual void Init(const YAML::Node& item) {
@@ -126,6 +163,11 @@ class Resize : public Transform {
   std::string interp_;
 };
 
+/*
+ * @brief
+ * This class execute center crop operation on image matrix. It crops the center
+ * of image matrix accroding to specified size.
+ * */
 class CenterCrop : public Transform {
  public:
   virtual void Init(const YAML::Node& item) {
@@ -145,6 +187,11 @@ class CenterCrop : public Transform {
   int width_;
 };
 
+/*
+ * @brief
+ * This class execute padding operation on image matrix. It makes border on edge
+ * of image matrix.
+ * */
 class Padding : public Transform {
  public:
   virtual void Init(const YAML::Node& item) {
@@ -172,7 +219,11 @@ class Padding : public Transform {
   int width_ = 0;
   int height_ = 0;
 };
-
+/*
+ * @brief
+ * This class is transform operations manager. It stores all neccessary
+ * transform operations and run them in correct order.
+ * */
 class Transforms {
  public:
   void Init(const YAML::Node& node, bool to_rgb = true);