| Abstract | This paper loosens the assumption that the total population growth rate is equal to the growth rate of working population in neoclassical production function, then the population structure is changing. We define the difference as the aging rate. If technical progress rate is exogenous, there would be saddle-shape balanced growth path in the economic system, and the output growth rate per capita depends on the difference between the technical progress rate and the aging rate. Besides improving the living standard, the technical progress need support the aged in the economy. To maximize the utility level per capita, the optimal aging rate should be zero for the aged do not benefit the production. In the framework of endogenous growth theory, the newly-born population will not only improve the technology, but also ehance the aging rate. The impact of the aging rate then depends on the difference of these two sides. Under strict conditions, there would be the optimal aging rate. Besides her positive role in the functions of the utility and the production, the government may guide the social strength to participate in the aging industry, and attract immigrants to increase the working population to cope with the aging population. However, the two children policy and delay retirement policy should be used cautiously. To solving the problem fundamentally, we should fully excavate the human capital and get the most of the newly-born population. |