Abstract The absence of mortgage and guarantee makes social capital more and more important. Social capital, as the core of social trust, provides a new perspective for alleviating the problem of household loan constraints. Based on the data of Chinese Household tracking Survey (CFPS) and Probit model, this paper empirically studies the impact of social trust on households’ loan availability. The results show that improving social trust can significantly improve the household’s loan availability as a whole. Heterogeneity test indicates that the above effects are more beneficial to rural households, low-income and low-asset families, and can significantly narrow the gap in the availability of loans among different classes. Mechanism analysis shows that improving social trust can enhance social mutual assistance, improve the social status of loan subjects, alleviate social exclusion and enhance the availability of household loans. Therefore, both the supply and demand of funds should change the traditional concept of lending and attach importance to the role of social trust. At the same time, they should also strengthen the construction of macro systems such as social trust culture and social credit system.