一般遇到這種問題，就跟牆有關啦，需要更換源。
用清華的源就非常好，去清華鏡像的官網看一下說明，https://mirrors.tuna.tsinghua.edu.cn/help/homebrew/
$ cd /usr/local/Homebrew $ git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/brew.git $ cd /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core $ git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/homebrew-core.git $ brew update 即可
復原
$ cd "$(brew --repo)" $ git remote set-url origin https://github.com/Homebrew/brew.git $ cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core" $ git remote set-url origin https://github.com/Homebrew/homebrew-core $ brew update "$(brew --repo)" 這里填/usr/local/Homebrew