话不多说，DiskMakerX，大小6.3M，下载地址：http://www.liondiskmaker.com/，然后准备好U盘和从官网下的Yosemite系统就可以开始了。
DiskMaker X (formerly Lion DiskMaker) is an application built with AppleScript that you can use with many versions of OS X to build a bootable drive from OS X installer program (the one you download from the App Store). As soon as you launch the application, it tries to find the OS X Install program with Spotlight. Then, it proposes to build a bootable install disk and make it look as nice as possible. It’s the easiest way to build an OS X Installer in a few clicks! Then you can use the Install drive to fully re-install the OS on a freshly formated drive, or install it on your many Macs without re-downloading the full installer.