Step 1: Visiting "about:config"

driver.get("about:config");

Step 2 : Run script that changes proxy

var setupScript=`var prefs = Components.classes["@mozilla.org/preferences-service;1"].getService(Components.interfaces.nsIPrefBranch); prefs.setIntPref("network.proxy.type", 1); prefs.setCharPref("network.proxy.http", "${proxyUsed.host}"); prefs.setIntPref("network.proxy.http_port", "${proxyUsed.port}"); prefs.setCharPref("network.proxy.ssl", "${proxyUsed.host}"); prefs.setIntPref("network.proxy.ssl_port", "${proxyUsed.port}"); prefs.setCharPref("network.proxy.ftp", "${proxyUsed.host}"); prefs.setIntPref("network.proxy.ftp_port", "${proxyUsed.port}"); //running script below driver.executeScript(setupScript); //sleep for 1 sec driver.sleep(1000);

Step 3: : Visit your site

driver.get("https://whatismyip.com");

 

参考：https://stackoverflow.com/questions/29776607/python-selenium-webdriver-changing-proxy-settings-on-the-fly