是Python的...尝试退出并在失败时捕获异常。

try:
    driver.quit()
except WebDriverException:
    pass

您可以使用类似于psutil的代码

from selenium import webdriver
import psutil

driver = webdriver.Firefox()

driver.get("http://tarunlalwani.com")

driver_process = psutil.Process(driver.service.process.pid)

if driver_process.is_running():
    print ("driver is running")

    firefox_process = driver_process.children()
    if firefox_process:
        firefox_process = firefox_process[0]

        if firefox_process.is_running():
            print("Firefox is still running, we can quit")
            driver.quit()
        else:
            print("Firefox is dead, can't quit. Let's kill the driver")
            firefox_process.kill()
    else:
        print("driver has died")

这是我想出来并喜欢的：

def setup(self):
    self.wd = webdriver.Firefox()

def teardown(self):
    # self.wd.service.process == None if quit already.
    if self.wd.service.process != None:
        self.wd.quit()

注意：如果驱动程序已经退出，driver_process=psutil.Process(driver.service.process.pid)将抛出异常。

Corey Golberg的答案是正确的方式。
但是，如果您真的需要深入了解，driver.service.process属性可以访问管理打开的浏览器的底层Popen对象，如果进程已经退出，process属性将为None，测试它是否真实将确定浏览器的状态：

from selenium import webdriver
driver = webdriver.Firefox()

# your code where the browser quits

if not driver.service.process:
    print('Browser has quit unexpectedly')

if driver.service.process:
    driver.quit()

除了Corey Goldberg's answer,和scign's answer之外：
不要忘记导入：

from selenium.common.exceptions import WebDriverException

此外，在Corey的回答中，代码将挂起大约10秒，同时试图关闭一个已经关闭的webdriver，然后再移动到except子句。