How to Jailbreak your iPhone on iOS 8.1 and install Cydia
 

First, backup your device and upgrade to iOS 8.1 if you haven’t already. Next, download the latest version of PanGu (I used version 1.0.1).

PanGu is Chinese, so don’t expect to be able to read anything unless you have a Chinese character set installed on your system (and know how to read it). Fortunately, it’s a pretty straightforward process for the most part.

Before you run PanGu, make sure you disable Find My iPhone. I also recommend disabling a passcode for now.

http://esotericsean.com/how-to-jailbreak-ios-8-1/