Great gaps exist among the Easten, Central and Western China.The Fourth Plenary Session of the Fifteenth Party Central Committee has set up the strategy of developing western China.It is necessary to bring out and analyze the trends and differences of population development, and to have a better understanding of the population environment for sustainable development in these reg ions.Based on the three regions officially divided in the Seventh- Five-Year Plan period, the author has made a projection o n population development from 1990 to 2060, and a comparative study on the population sizes, age structures and labor resources.