In the case of population dividend which tends to disappear, to choose a new driving force of economic growth has become essential. In this “new normal” economy, in essence, the supply-side reform is to optimize the allocative capital, labor and land. Raising human capital may be the source of economic growth in the new situation. In academia today, there is consensus that human capital is an important driver of economic growth, but how human capital promotes economic growth mechanism remains controversial. This paper discusses mechanism and classification of heterogeneous effects of human capital on economic growth, on which hypothesis is based. It uses demographic data from the country's 30 provinces and autonomous regions to analyze and verify this. The last comprehensive actual situation in China is concluded.