No, China doesnt control bitcoin, no one controls bitcoin. Because the number of Chinese who are using bitcoin is too high and the fact that China has many mining companies and biggest mining power, everything they do would surely affect the price of bitcoin but that doesnt mean they own all the bitcoin and have a right to put a stop to it anytime they want.
Of course they don't have complete control, no one does, but they have a LOT of influence over bitcoin due to their mining power. Them being able to affect prices so drastically already gives them more control than we users have, no one is saying they literally control the idea but since they have more of a hold on it than any other institution or company, it's fair to say they control it.