Abstract：
The theory of new-economic growth points out that human capital is as important as physical capital in economic growth. But many empirical tests do not support this conclusion. We believe that there must be the optimal level in the investment of human capital based on the wealth constraints of the social total population and the entire society. The paper uses the panel data of 1978~2010 to estimates the value of in the accumulation function of human capital. Some conclusions are made as follows: first, the gold value to maximize the whole society output is 20.85 years and the gold value to maximize personal gains is 14.63 years; second, the private sector has no interest in investing high-level human capital; third, the increase of economy and human capital stock are not always consistent when the proportion of the elderly people has significantly increased.
2014 
