清华大学镜像网址

https://mirrors.tuna.tsinghua.edu.cn/

$ pod repo remove master
$ pod repo add master https://mirrors.tuna.tsinghua.edu.cn/git/CocoaPods/Specs.git
$ pod repo update

or

$ cd ~/.cocoapods/repos
$ pod repo remove master
$ git clone https://mirrors.tuna.tsinghua.edu.cn/git/CocoaPods/Specs.git master

Podfile在最开头加上:

source 'https://mirrors.tuna.tsinghua.edu.cn/git/CocoaPods/Specs.git'