Abstract: A new concept of sport social capital in the process of China's sport power construction is developed by means of integrating social capital with mass sport participation. Empirical analysis based on CHNS 2015 shows that: at the collective level, groups with larger status advantage have a higher stock of sport social capital; at the individual level, the higher the stock of sport social capital, the better physical and mental health, and the higher life satisfaction of the residents. These findings suggest that sport social capital is an important mechanism to help build the national power of sports, and it requires a special effort to increase the sport social capital of disadvantaged groups. The promotion of sport social capital should be based on the local reality and appreciate its cultural advantages. The gaps of sport social capital in different areas should be narrowed thus to achieve the balanced development of citizens' fitness and subjective wellbeing.