diff --git a/_includes/head.html b/_includes/head.html
index 929c60b..44da8c9 100644
--- a/_includes/head.html
+++ b/_includes/head.html
@@ -5,12 +5,10 @@
   {%- seo -%}
   <link rel="stylesheet" href="{{ "/assets/main.css" | relative_url }}">
   <link rel="stylesheet" href="{{ "/assets/css/mystyle.css" | relative_url }}">
-  <link rel="stylesheet" href="{{ "/assets/css/PATkatex.css" | relative_url }}">
   <link rel="shortcut icon" type="image/x-icon" href="{{ "favicon.ico" | relative_url }}">
   {%- feed_meta -%}
   {%- if jekyll.environment == 'production' and site.google_analytics -%}
     {%- include google-analytics.html -%}
   {%- endif -%}
   {%- include mathjax.html -%}
-  {%- include katex.html -%}
 </head>
diff --git a/_includes/katex.html b/_includes/katex.html
deleted file mode 100644
index 0423714..0000000
--- a/_includes/katex.html
+++ /dev/null
@@ -1,9 +0,0 @@
-<!-- Katex files -->
-<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/katex.min.css" integrity="sha384-9eLZqc9ds8eNjO3TmqPeYcDj8n+Qfa4nuSiGYa6DjLNcv9BtN69ZIulL9+8CqC9Y" crossorigin="anonymous">
-
-<!-- The loading of KaTeX is deferred to speed up page rendering -->
-<script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/katex.min.js" integrity="sha384-K3vbOmF2BtaVai+Qk37uypf7VrgBubhQreNQe9aGsz9lB63dIFiQVlJbr92dw2Lx" crossorigin="anonymous"></script>
-
-<!-- To automatically render math in text elements, include the auto-render extension: -->
-<script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.0/dist/contrib/auto-render.min.js" integrity="sha384-kmZOZB5ObwgQnS/DuDg6TScgOiWWBiVt0plIRkZCmE6rDZGrEOQeHM5PcHi+nyqe" crossorigin="anonymous"
-    onload="renderMathInElement(document.body);"></script>
diff --git a/_includes/mathjax.html b/_includes/mathjax.html
index b69b59a..817f1e8 100644
--- a/_includes/mathjax.html
+++ b/_includes/mathjax.html
@@ -11,5 +11,6 @@
   });
 </script>
 <script type="text/javascript" async
-        src="https://cdn.bootcss.com/mathjax/2.7.5/MathJax.js">
+        src="https://cdn.bootcss.com/mathjax/2.7.5/MathJax.js?config=TeX-MML-AM_CHTML">
+  /* https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/latest.js */
 </script>
diff --git a/assets/css/PATkatex.css b/assets/css/PATkatex.css
deleted file mode 100644
index 59de2a8..0000000
--- a/assets/css/PATkatex.css
+++ /dev/null
@@ -1,864 +0,0 @@
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diff --git a/source/build.py b/source/build.py
index c8727cd..747a2a3 100755
--- a/source/build.py
+++ b/source/build.py
@@ -7,6 +7,7 @@ import os
 import sys
 import re
 import argparse
+from bs4 import BeautifulSoup
 from subprocess import run, PIPE, CalledProcessError
 import config
 
@@ -55,7 +56,21 @@ class FileBuilder:
         frontmatter += "---\n\n"
         return frontmatter
 
-    def filename(self):
+    def _processkatex(self, html):
+        """
+        replace all the 'katex' class spans with simple latex string
+        """
+        soup = BeautifulSoup(html, "html.parser")
+        katex_spans = soup.find_all("span", class_="katex")
+        for katex_span in katex_spans:
+            katex_span.mrow.decompose()
+            mathstr = katex_span.find("math")
+            mathjax = soup.new_tag("span")
+            mathjax.string = "${}$".format(mathstr.string)
+            katex_span.replace_with(mathjax)
+        return str(soup)
+
+    def _filename(self):
         return os.path.join(config.md_dir, "{}{:04}.md".format(self.c, self.i))
 
     def read_html(self):
@@ -70,7 +85,8 @@ class FileBuilder:
                     index=self.i,
                     title=lines[0].rstrip(),
                     lang="(C语言实现)")
-        content = lines[1:]
+        content = self._processkatex("".join(lines[1:]))
+
         return title, content
 
     def read_code(self):