Originally Posted by
moondog
Show US passport to the airline and Chinese passport to the officials. I have a friend who does this drill ~10x per year, though with a HK ID (instead of a PRC passport). One time, an official caught a glimpse of his US passport, and deported him to HK immediately. He returned the next day, but told me it wasn't a pleasant experience.
With Chinese passport, entry is not a problem. Exit is. You need something to exit and it must have an entry stamp on it. With HK id I assume it's much easier.