You have problem with the terminal where you are outputting the result. The script works fine and if you output data to file you will get it correctly.
Example:
import urllib2
from bs4 import BeautifulSoup
url = 'http://www.bbc.co.uk/zhongwen/simp/'
page = urllib2.urlopen(url).read().decode("utf-8")
dom = BeautifulSoup(page)
data = dom.findAll('meta', {'name' : 'keywords'})
with open("test.txt", "w") as myfile:
myfile.write(data[0]['content'].encode("utf-8"))
test.txt:
BBC中文网,主页,bbcchinese.com, email news, newsletter, subscription, full text
Which OS and terminal you are using?