Unless the chinese characters are images vs. fonts how they look on your pc has nothing to do with how they'll look on a reader - sounds like you're using a bad font with Calibre or whatever reader you're using on the PC.
I'm not sure if the Kindle supports chinese at all.
There was a similar discussion on this earlier today/yesterday - never hurts to browse/search the forums to see if there are answers already:
https://www.mobileread.com/forums/sho...d.php?t=144805