html = r'{"code":404,"msg":"\u8be5\u8d44\u6e90\u4e0d\u5b58\u5728"}'

print(html)
# {"code":404,"msg":"\u8be5\u8d44\u6e90\u4e0d\u5b58\u5728"}

print(html.encode('utf-8').decode('unicode-escape'))
# {"code":404,"msg":"该资源不存在"}