can a former chines citizen who has become A U.S. citicen return to China at a leter date to live?

Gerry, do you mean "living permanently"? If so, I am afraid that it's difficult to achieve this. You know, it's very difficult to apply permanent resident permit. Every year, just around 200 foreigners acquire permanent resident permits. You may try to apply for a Q1 or Z visa so that you can live longer in mainland China.