先看这篇文章：
https://www.cnblogs.com/onelikeone/p/13111520.html
http://download.calibre-ebook.com/1.48.0/ 支持window xp
https://calibre-ebook.com/download calibre
https://www.fosshub.com/Calibre.html win 64 bit calibre 下载地址
calibre is a powerful and easy to use e-book manager. Users say it’s outstanding and a must-have. It’ll allow you to do nearly everything and it takes things a step beyond normal e-book software. It’s also completely free and open source and great for both casual users and computer experts.
PS：
京东阅读 也可以打开epub
手机端：