D:\Program Files\python_3_6_4>python -m pip install --upgrade pip
Cache entry deserialization failed, entry ignored
Collecting pip
  Cache entry deserialization failed, entry ignored
  Downloading https://files.pythonhosted.org/packages/a4/6d/6463d49a933f547439d6b5b98b46af8742cc03ae83543e4d7688c2420f8b/pip-21.3.1-py3-none-any.whl (1.7MB)
    100% |████████████████████████████████| 1.7MB 299kB/s
Installing collected packages: pip
  Found existing installation: pip 9.0.1
    Uninstalling pip-9.0.1:
      Successfully uninstalled pip-9.0.1
Successfully installed pip-21.3.1

 

特别注意：

如果安装了多个版本的python

要在正确的位置执行 python -m pip install --upgrade pip