发送原始邮件数据没有问题：raw_data = '__VIEWSTATE=%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%2FRQ%2BPP7XKuKE1Yc7MfMt6j3NmJGEldOg%3D%3D&__VIEWSTATEGENERATOR=98F5786E&__EVENTVALIDATION=%2FwEWPwLc4fuhDgLPv6LBCALyveCRDwKt9JiEDQKyzcaDDQLQzfKVCgLi0PKVCgKwgbuWDQK4qIuIDAKDhrjXCAKT%2B%2B00AqGSlqELAoPh28wDAvSit9QCAsvep4YKAtj71VwC9pD07goC8rfjvgoCoryYqAECv6uC5A4C2dmTnQUCrdnKtgICyJiTrwsCjLGlBQKNsaUFAo6xpQUCj7GlBQKIsaUFAomxpQUCirGlBQKbsaUFApSxpQUCjLHlBgKMsekGAoyx7QYCjLHRBgKMsdUGAoyx2QYCjLHdBgKMscEGAoyxhQUCjLGJBQKNseUGAo2x6QYCjbHtBgKNsdEGAo2x1QYCjbHZBgKNsd0GAo2xwQYCjbGFBQKNsYkFAo6x5QYCjrHpBgLopM%2F9CwLsyZauAQL4oO3lBAK8yuqBCwL1hriZBwLUpvv7CALsqKmSDgLqoY%2BHAwLCi9reA5HII3R9bARNVKmrB9WBnfeJepHFJrdPAtcLnXlE%2BdKP&username2=gfk7ljlyks&password=boolbool1&password2=boolbool1&email=myeail%40gf.com&fname=&lname=&phone=&street=&city=&BYear=&Bmonth=%D7%99%D7%A0%D7%95%D7%90%D7%A8&Bday=1&career=&signature=&homepage=&icq=&Morehobbies=&allowmail=on&SendNews=on&chkterms=on&btnSubmit=%D7%9C%D7%97%D7%A5+%D7%9C%D7%A1%D7%99%D7%95%D7%9D+%D7%94%D7%94%D7%A8%D7%A9%D7%9E%D7%94+%D7%9C%D7%90%D7%AA%D7%A8'

requests.post(url, data=raw_data)

一个小的好处是你的数据已经被百分比编码。

从文档字符串：post(url, data=None, json=None, **kwargs)

Sends a POST request.

:param url: URL for the new :class:`Request` object.

:param data: (optional) Dictionary, bytes, or file-like object to send in the body of the :class:`Request`.

:param json: (optional) json data to send in the body of the :class:`Request`.

:param \*\*kwargs: Optional arguments that ``request`` takes.

:return: :class:`Response ` object

:rtype: requests.Response

因此data可以是字典、字符串/字节或类似文件的对象。

也许您需要像这样指定Content-Type头：requests.post(url, data=raw_data, headers={'Content-Type': 'application/x-www-form-urlencoded'})