Bad news for you. Most of the cards in China are centered around immediate rewards... essentially discounts with partners, rather than points and miles. The points game in Asia is TERRIBLE, with the best one I've seen so far being the Cathay Pacific Amex (In Hong Kong). I just use my US cards that don't have a Forex fee instead. There's still a small differential in the exchange rate, but it's still generally better than the abysmal exchange rates you would be getting from a money changer or bank anyway.

I may have missed some in China, as I've mostly just been exposed to the HK offerings, but they've been generally bad from what I've seen.