from lxml import  etreehtml = '''<li class="tag_1">需要的内容1<a>需要的内容2</a></li>
'''selector =  etree.HTML(html )
contents  =  selector.xpath ( '//li[@class = "tag_1"]')
contents1  =  selector.xpath ( '//li[@class = "tag_1"]')[0]
contents2  =  contents1.xpath('string(.)')
contents3  =  selector.xpath ( '//li[@class = "tag_1"]/text()')
print(contents)  #[<Element li at 0x2c55e88>]
print(contents1) # <Element li at 0x2c55e88>
print(contents2)
print(contents3)

输出

D:\Python\venv\Scripts\python.exe D:/Python/venv/test9.py
[<Element li at 0x2c75ec8>]
<Element li at 0x2c75ec8>
需要的内容1需要的内容2['需要的内容1\n         ', '\n          ']Process finished with exit code 0

string(.)可以用于提取标签嵌套标签的内容。