Generally encountered this problem, just like the wall about the matter, the source needs to be replaced.
A source of Tsinghua is very good, go to Tsinghua University's official website to look at the mirror description, 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 To
recovery
$ 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)" here fill in / usr / local / Homebrew