1、You are using pip version 7.1.2, however version 10.0.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
2、在命令窗口中输入命令运行：python -m pip install --upgrade pip，安装即可成功
3、然后在运行：pip install -U selenium，安装即可成功
4、pycharm运行selenium
from selenium import webdriver
browser = webdriver.Firefox()
browser.get("https://www.baidu.com")
# browser.quit()