diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3258efe..469414d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+## [v3.3.1] - 2021-12-10
+
 ### Changed
 
 - 同步新版《撰写手册》（2016 年 12 月版，2019 年 第 3 次印刷）（#291）。
@@ -256,7 +258,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - 优化图注、算法的行距。
 - 二级以下节标题编号下采用“1.”、“(1)”、“①”。
 
-[Unreleased]: https://github.com/ustctug/ustcthesis/compare/v3.3.0...HEAD
+[Unreleased]: https://github.com/ustctug/ustcthesis/compare/v3.3.1...HEAD
+[v3.3.1]: https://github.com/ustctug/ustcthesis/compare/v3.3.0...v3.3.1
 [v3.3.0]: https://github.com/ustctug/ustcthesis/compare/v3.2.1...v3.3.0
 [v3.2.1]: https://github.com/ustctug/ustcthesis/compare/v3.2...v3.2.1
 [3.1.06]: https://github.com/ustctug/ustcthesis/compare/v3.2...v3.1.06
diff --git a/ustcthesis-doc.tex b/ustcthesis-doc.tex
index 18681c3..1024f47 100644
--- a/ustcthesis-doc.tex
+++ b/ustcthesis-doc.tex
@@ -113,7 +113,7 @@
 \title{\cls{ustcthesis} 使用说明}
 \author{Zeping Lee\thanks{zepinglee AT gmail.com} \and
         seisman\thanks{seisman.info AT gmail.com} }
-\date{v3.3.0\qquad 2021-03-18}
+\date{v3.3.1\qquad 2021-12-10}
 \maketitle
 
 
diff --git a/ustcthesis.cls b/ustcthesis.cls
index ed008a3..f088e13 100644
--- a/ustcthesis.cls
+++ b/ustcthesis.cls
@@ -11,8 +11,8 @@
 %
 
 \NeedsTeXFormat{LaTeX2e}[2017/04/15]
-\newcommand\ustcthesisversion{v3.3.0}
-\ProvidesClass{ustcthesis}[2020/04/03 {\ustcthesisversion} USTC thesis template]
+\newcommand\ustcthesisversion{v3.3.1}
+\ProvidesClass{ustcthesis}[2021/12/10 {\ustcthesisversion} USTC thesis template]
 
 % 报错和警告
 \newcommand\ustc@error[1]{%