Some people think they can use Chinese passport for entering China, and Canadian passport for back to Canada. But the truth is it doesn't work.
After you get Canadian citizen, your PR card will not be valid any more. Yes you can enter China with Chinese passport, but how can you leave China? Without a valid visa or PR card, you will be refused by the border service. If you try to use Canadian passort to leave China, you will be charged with illegal entering, since you don't have any legal entering record on you Canadian passport.