How to maintain non-english character in posts’ permalink?

For instance, I want to make my permalink showing like this: http://wordpressblog.com/posts/喜劇/ , some japanese words in it.

But instead of this, it is actually turn out showing this: http://wordpressblog.com/posts/%e5%96%9c%e5%8a%87/

How can I maintain non-english character in posts’ permalink?