diff --git a/doc/source/vcs.rst b/doc/source/vcs.rst
index e79f741707ceabd93d9e6325050ae4ab8b6fe6c4..6e7cfeac4b29610799f531f48a03ab74bd409f7e 100644
--- a/doc/source/vcs.rst
+++ b/doc/source/vcs.rst
@@ -134,8 +134,8 @@ a code reviewer is required to merge approved code revisions into ``main`` branc
 .. _csst-l1: https://csst-tb.bao.ac.cn/code/csst-l1
 
 
-Code review
------------
+Code review mechanism
+---------------------
 
 Starting from C7, developers of all packages should NOT directly push any code
 to *main* branch which is protected.
@@ -146,3 +146,76 @@ Developers should switch to a ``dev`` branch before doing anything.
 Then commit code and push them to ``dev`` branch.
 
 
+Workflow with ``dev`` branch
+----------------------------
+
+.. code-block::
+    :caption: As a developer:
+
+    (base) cham@MBP16 csst_proto % git branch -a # show all branch
+      dev
+    * main
+      remotes/origin/main
+    (base) cham@MBP16 csst_proto % git checkout dev # check out dev -> then you are in dev branch
+    M       doc/source/conf.py
+    M       doc/source/index.rst
+    M       doc/source/integration.rst
+    M       doc/source/vcs.rst
+    Switched to branch 'dev'
+    (base) cham@MBP16 csst_proto % git status # view code changes
+    On branch dev
+    Changes not staged for commit:
+      (use "git add <file>..." to update what will be committed)
+      (use "git restore <file>..." to discard changes in working directory)
+            modified:   doc/source/conf.py
+            modified:   doc/source/index.rst
+            modified:   doc/source/integration.rst
+            modified:   doc/source/vcs.rst
+
+    Untracked files:
+      (use "git add <file>..." to include in what will be committed)
+            doc/contents.md
+
+    no changes added to commit (use "git add" and/or "git commit -a")
+    (base) cham@MBP16 csst_proto % git add doc/source/*.rst doc/source/conf.py # add your code changes
+    (base) cham@MBP16 csst_proto % git commit -m "updated doc: author info and docker info" # commit your changes
+    [dev bbed3fa] updated doc: author info and docker info
+     4 files changed, 73 insertions(+), 4 deletions(-)
+    (base) cham@MBP16 csst_proto % git push origin dev # as a developer you are not allowed to push to main branch
+    Enumerating objects: 15, done.
+    Counting objects: 100% (15/15), done.
+    Delta compression using up to 10 threads
+    Compressing objects: 100% (8/8), done.
+    Writing objects: 100% (8/8), 1.67 KiB | 1.67 MiB/s, done.
+    Total 8 (delta 6), reused 0 (delta 0), pack-reused 0
+    remote:
+    remote: To create a merge request for dev, visit:
+    remote:   http://10.3.10.28/code/csst-l1/csst_proto/-/merge_requests/new?merge_request%5Bsource_branch%5D=dev
+    remote:
+    To https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto.git
+     * [new branch]      dev -> dev
+
+.. code-block::
+    :caption: As a code reviewer:
+
+    (base) cham@MBP16 csst_proto % git checkout main # check out main branch
+    Switched to branch 'main'
+    Your branch is up to date with 'origin/main'.
+    (base) cham@MBP16 csst_proto % git merge dev # merge dev branch into main AFTER view changes
+    Updating d9f64d3..bbed3fa
+    Fast-forward
+     doc/source/conf.py         |  2 +-
+     doc/source/index.rst       | 11 +++++++++++
+     doc/source/integration.rst | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
+     doc/source/vcs.rst         | 14 ++++++++++++++
+     4 files changed, 73 insertions(+), 4 deletions(-)
+    (base) cham@MBP16 csst_proto % git push origin main # push to remote main branch
+    Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
+    To https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto.git
+       d9f64d3..bbed3fa  main -> main
+
+.. note::
+    As a developer, you can also create a merge requrest to ask code reviewers to merge your changes on GitLab.
+    Click ``Merge requests`` tag, click ``
+
+.. image:: vcs/merge_request.png
diff --git a/doc/source/vcs/merge_request.png b/doc/source/vcs/merge_request.png
new file mode 100644
index 0000000000000000000000000000000000000000..45575e6a5f6c4a1b7154283ac53240107265c93a
Binary files /dev/null and b/doc/source/vcs/merge_request.png differ