例：抓取PhotoShop视频教程 网址http://www.mxiaobei.com/?id=424

import requests
import re
from bs4 import BeautifulSoup
import time

dicts = {}
list1 = set()

print('start')

ua = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.87 Safari/537.36'

urls = 'http://www.mxiaobei.com/?id='

for index in range(451, 565):
    r = requests.get(urls + str(index), headers = {'user-agent': ua })
    r.encoding = 'utf-8'
    soup = BeautifulSoup(r.text, 'lxml')
    title = soup.find(name='h2')
    mp4url = soup.find('div', id='CuPlayer')
    if mp4url is None:
        list1.add(index)
        continue
    mpurl = re.search('http.*?mp4', mp4url.text)
    dicts[title.text] = mpurl.group()
    #print(index)
    #time.sleep(1)
    #print(title.text + ' : ' + dicts[title.text])
print(dicts)
print(list1)
for temp in dicts.items():
    #time.sleep(1)
    r = requests.get(temp[1], stream=True)
    with open(temp[0] + '.mp4', "wb") as mp4:
        for chunk in r.iter_content(chunk_size=1024 * 1024):
            if chunk:
                mp4.write(chunk)
    print(temp[0]+'下载完成')
print('end!')

• BeautifulSoup: https://beautifulsoup.readthedocs.io/zh_CN/v4.4.0/
• Requests: http://cn.python-requests.org/zh_CN/latest/