If China people acquire foreign nationality and China people live in foreign countries, can they acquire China nationality again after returning to China for many years? Is he still from China?

This is a question of immigration and naturalization. If you become a foreign citizen, China does not recognize dual citizenship, so China citizenship will be revoked. Because of information asymmetry or deliberate concealment, many China people who joined foreign countries still retain their China nationality, but China people who have lived abroad for many years are already foreign Chinese. If they want to restore China nationality, they must apply for naturalization again according to the immigration regulations.