Will it be easier to get into an American university from Canada than from China?

It's not as easy as China, because American universities require SAT scores no matter where people are, that is to say, they are treated equally. You have to learn the SAT of non-native English in Canada, while China applicants can learn the SAT of their native language in their own country, and there are many cattle schools offering SAT classes in China. I'm afraid the score will be higher than yours. But if you go to high school abroad, your language will be better than that of domestic students, and it may be easier after you go to college.