Using the samples of non financial listed companies from 2003 to 2019 in China, this paper intends to study how social capital in different provinces influence the shadow banking levels of non financial enterprises and its internal mechanism. Empirical results show that there is a significant U shaped relationship between regional social capital and the shadow banking behavior of non financial enterprises. The mechanism test finds that social capital influence the shadow banking of non financial enterprises through mitigating financing constraints and reducing information asymmetry channels. Further analysis shows that economic policy uncertainty will weaken the relationship between social capital and shadow banking behavior of non financial enterprises, and the relationship between social capital and shadow banking of non financial enterprises has firm heterogeneity, and the above results have passed the robust test.