Looking from the existing research, improving the social capital of the poverty population is an effective way to promote the population quality and the income growth of the poor people. Based on the existing research, with the rural poor households in Sichuan Liangshan as the research object, this article used factor analysis to measure social capital stock, and then analyzed the influence of social capital on the income of the poor peasant households in that region, through the reconstructed production function. The results show that the poor households’ social capital has a significant impact on their income level, and the effect degree varies in different income levels.