Temporary modifications (recommended) pypi mirror source: If there is an error untrust, the site can be used beginning with https, or add --trusted PIP install -i https://pypi.tuna.tsinghua.edu.cn/simple/ - trusted-host pypi.douban.com permanent pypi source modification (not recommended): Windows: enter the user directory cd% HOMEPATH% md PIP cd PIP cd> pip.ini. add content: [, Ltd. Free Join] index-url = HTTP: // pypi.douban.com/simple [the install] Trusted-Host = pypi.douban.com =============================== ==================== Linux: CD ~ mkdir .pip CD .pip && VI pip.conf add content: [Global] index-URL = HTTP: // PyPI .douban.com / Simple [the install] Trusted-Host = pypi.douban.com --index-url is mirroring the domestic pip source Ali cloud http://mirrors.aliyun.com/pypi/simple/ China University of Science and Technology https://pypi.mirrors.ustc.edu.cn/simple/ watercress (douban ) http://pypi.douban.com/simple/ https://pypi.tuna.tsinghua.edu.cn/simple/ Tsinghua University , University of Science and technology of China http://pypi.mirrors.ustc.edu.cn/simple /