Constructing a mediating effect, this paper empirically tests the path of the impact of human capital structure on the quality of China’s economic growth and analyzes the regional heterogeneity and sub dimensional heterogeneity. The results show that, firstly, compared with the stock of human capital, the optimization of human capital structure is more conducive to the improvement of the quality of regional economic growth. Secondly, the optimization of human capital structure plays a significant role in promoting the quality of China’s economic growth, especially in the eastern region. Thirdly, the optimization of human capital structure has a positive impact on the process index and outcome index of economic growth quality, and the promotion effect of the high level level of regional human capital structure on the quality process index of economic growth is greater than that on the outcome index. Fourthly, human capital structure can promote the quality of economic growth through industrial structure and technological structure, and the intermediary effect of industrial structure upgrading is greater than that brought by technological structure upgrading.