<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>纯CSS实现Div高度根据自适应宽度（百分百调整）</title> </head> <style> .father { width: 100px; height: 100px; background: #222 } .element { width: 50%; height: 0; padding-bottom: 50%; background: #eee; } </style> <body> <div class="father"> <div class="element"> 123 </div> </div> </body> </html>