With the world population rising above the 5 billion mark this year，the impact of population on economic，scientific，technological and social development has increasingly attracted wide attention. China is a country characterized by its large population and its lack of a solid industrial base. Thus，research on the impact of population on economic development appears to be of the population. Population age structure is an important though easily neglected factor which deserves extensive and in-depth research. This paper is an attempt to look at a few of the most fundamental problems that bear upon national economic development from the perspective of changes in the population age structure.