If you're using your own computer and you're sensible then no, it's just as safe in China. Although the net is heavily censored they can't (at least not to anyone's knowledge) crack the encryption used for websites beginning with https://. If they can then it's the government who can and they probably have your bank details anyway ;-)
Normal net safety rules apply- check the SSL certificate (your browser should display a little padlock) and make sure your laptop isn't full of viruses.
Using Internet cafes is a different story, though. You've no good way of telling if they have keyloggers installed which record your username/password or other security details. They are probably best avoided for online banking etc if you're really concerned.