Mac 终端跑入即可

cd /usr/local/
git remote set-url origin http://mirrors.ustc.edu.cn/homebrew.git
#或者这个：
git remote set-url origin git://mirrors.tuna.tsinghua.edu.cn/homebrew.git
brew update

如果还是感觉慢，看看这个：https://mirrors.tuna.tsinghua.edu.cn/help/homebrew/

cd ~/tmp
git clone git://mirrors.tuna.tsinghua.edu.cn/homebrew.git
rm -rf /usr/local/.git
rm -rf /usr/local/Library
cp -R homebrew/.git /usr/local/
cp -R homebrew/Library /usr/local/

然后重试update。

使用homebrew-science或者homebrew-python

cd /usr/local/Library/Taps/homebrew/homebrew-science
git remote set-url origin git://mirrors.tuna.tsinghua.edu.cn/homebrew-science.git

cd /usr/local/Library/Taps/homebrew/homebrew-python
git remote set-url origin git://mirrors.tuna.tsinghua.edu.cn/homebrew-python.git

brew update

也可以使用coding.net提供的镜像

$ cd /usr/local && git remote set-url origin https://git.coding.net/homebrew/homebrew.git

$ brew update