Abstract: Sports participation is considered to be an effective means to improve people's quality of life, but the influence mechanism between the two lacks the explanation path of social capital. Using 1,198 valid data from the 2021 nationwide survey with random sampling at different stages, the relationships among sports participation, social capital and life quality of urban residents in China are empirically analyzed. The results show that the quality of life of urban residents is good, but there are group differences; sports participation can directly improve the quality of life of urban residents. Finally, social capital has a mediating effect when sports participation influences the quality of life, with a greater contribution rate of collective social capital, compared with individual capital.