Is China an atheist country?
No. China is a Humanist country. Many Chinese believe in the existence of supernatural beings so they are not atheists; however, supernatural beings, be they ghosts or spirits, never have a higher position than Human Being in the universe. Supernatural beings may be dangerous or powerful, just like tigers are dangerous and powerful, but they play a role inferior to Human Being in the universe.
Confucius said that respect supernatural beings and keep a distance from them. Confucius didn't give supernatural beings any chance to mess up with Human society and politics. But it does not mean Confucius does not believe in the existence of a variety of gods.
Chinese do worship some gods; however, gods have no authority over Human affairs. Chinese deal with gods, should they believe that there is a god, just as they a dealing with other natural phenomena without scientific explanations. Chinese negotiate with supernatural beings, trade with them, make love with them, and drive them out of life, through a variety of ceremonies. But man is always in charge of the universe. Human is in the center of the universe.