Can qq sports only synchronize the health of Apple phones? How can I synchronize with Xiaomi Sports?

No, but the effect is the same, because in the absence of peripherals, the data is collected by the health app, and the data of any other app is read from health, so it doesn't matter who connects who. The app supported by peripherals will only store data that meets Apple's specifications, and the others are still visible only in the app, and other apps have no access.