China passport+American green card+Canadian passport.

Well, theoretically, it seems no problem for you to do so. But you can't go back and forth between Canada. I have to go through the United States every time, and I can't buy a joint ticket. If something goes wrong, it may be seen by the customs, and then all your efforts will be in vain.

That's not the problem. The key point is that if you encounter something during your stay in China, you can only handle it as a citizen of China, sometimes it is not as convenient as a foreign citizen. I read a piece of news that some people have Canadian citizenship, but they still enter China with China passports. A car accident happened during his stay in China. As his entry documents show that he is a citizen of China, he can only make compensation according to the compensation standard of China citizens. Of course, this is an extreme example, but it also shows that retaining the China passport can bring some convenience, but we should fully consider the risks brought by this practice and make a decision after weighing.

Anyway, I don't want to leave like this. . .