Under the dual influence of domestic and international situation, China''s economy has entered the stage of "new normal". The slowing down of economic growth brings new contradictions and challenges. The economic growth mode has gradually changed from extensive to intensive, but the previous economic theories have certain limitations in the new economic stage. In this paper, we use the leading-edge modeling methods of the mainstream macroeconomics to include the four existing economic growth theories in a comprehensive model, which combines human capital investment, financial capital investment, physical capital investment, innovation and entrepreneurship activities, and Nash game mechanism in an integrated analytical framework to make an important summary and expansion of economic growth theory literature. Through calibration and numerical simulation, the basic conclusion of the theoretical model is drawn: Although human capital accumulation can promote economic growth through innovation and entrepreneurship, its effect is still decreasing, showing the attributes of neoclassical growth model.