Here’s an example of how to create an HTML message with an alternative plain text version: [2]
#!/usr/bin/env python3
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
# me == my email address
# you == recipient's email address
me = "my@email.com"
you = "your@email.com"
# Create message container - the correct MIME type is multipart/alternative.
msg = MIMEMultipart('alternative')
msg['Subject'] = "Link"
msg['From'] = me
msg['To'] = you
# Create the body of the message (a plain-text and an HTML version).
text = "Hi!\nHow are you?\nHere is the link you wanted:\nhttp://www.python.org"
html = """\
<html>
<head></head>
<body>
<p>Hi!<br>
How are you?<br>
Here is the <a href="http://www.python.org">link</a> you wanted.
</p>
</body>
</html>
"""
# Record the MIME types of both parts - text/plain and text/html.
part1 = MIMEText(text, 'plain')
part2 = MIMEText(html, 'html')
# Attach parts into message container.
# According to RFC 2046, the last part of a multipart message, in this case
# the HTML message, is best and preferred.
msg.attach(part1)
msg.attach(part2)
# Send the message via local SMTP server.
s = smtplib.SMTP('localhost')
# sendmail function takes 3 arguments: sender's address, recipient's address
# and message to send - here it is sent as one string.
s.sendmail(me, you, msg.as_string())
s.quit()
选自 https://docs.python.org/3.3/library/email-examples.html
msg.attach(html) ok
msg.attach(text) 【text没有显示， 也没有出现在附件里面， 那么plain 和 html同时出现，如何处理的呢？】
msg.attach(image) ok
msg.attahc(xxxx) ok
印象中，好像text/plain和text/html是分不同终端显示的，
比如web收信和client收信，
客户端有时候不显示html的代码。
也有的只显示text文字说明。