The same group that released it jailbreak for iOS 7 was also released the jailbreak for iOS 8.1. Currently, the tool only works on Windows systems, it is in Chinese, and does not install on Cydia by default.
The jailbreak currently shows several errorand we do not recommend you to try it on your device. If you use a password accessIf the system crashes, there are problems with Cydia, and enough tweaks they do not work.
Cydia has already been notified about the new iOS, but requires manual installation by SSH. If you're bold, you can download the jailbreak tool from the website Pangu.
We recommend that you do not do so and wait until they fix the bugs.