来自http://docs.python.org/library/email.header.html
from email.message import Message
from email.header import Header
msg = Message()
msg['Subject'] = Header('主題', 'utf-8')
print msg.as_string()
主题:=?utf-8?b?5Li76aGM?=
更简单:
from email.header import Header
print Header('主題', 'utf-8').encode()
=?utf-8?b?5Li76aGM?=