diff --git a/src/Engine.js b/src/Engine.js
index cac3c646..d66eb466 100644
--- a/src/Engine.js
+++ b/src/Engine.js
@@ -19,7 +19,7 @@ import NestedError, { $expectTarget, $expectInherit, $expectInstance } from './u
 import CryptoJS from 'crypto-js';
 import SyntaxBase from './core/SyntaxBase';
 import ParagraphBase from './core/ParagraphBase';
-import { PUNCTUATION, longTextReg, base64Reg, imgBase64Reg, imgDrawioXmlReg } from './utils/regexp';
+import { PUNCTUATION, longTextReg, imgBase64Reg, imgDrawioXmlReg } from './utils/regexp';
 import { escapeHTMLSpecialChar } from './utils/sanitize';
 import Logger from './Logger';
 import { configureMathJax } from './utils/mathjax';
@@ -252,11 +252,6 @@ export default class Engine {
       this.cachedBigData[cacheKey] = m2;
       return `${m1}${cacheKey}}`;
     });
-    $md = $md.replace(base64Reg, (whole, m1, m2) => {
-      const cacheKey = `bigDataBegin${this.hash(m2)}bigDataEnd`;
-      this.cachedBigData[cacheKey] = m2;
-      return `${m1}${cacheKey}}`;
-    });
     $md = $md.replace(longTextReg, (whole, m1, m2) => {
       const cacheKey = `bigDataBegin${this.hash(m2)}bigDataEnd`;
       this.cachedBigData[cacheKey] = m2;