Abstract: This paper firstly introduces the parameters of social capital and mortgage loan and the social optimal lending model constructed on the basis of Cobb-Douglas function to conduct an analysis. The results show that social capital helps to improve farmers’ availability to loans. Secondly, from the perspectives of the three groups, i.e., all the people, the medium to high-income group and the low-income group, it conducts an empirical analysis of the data from the farmers’ survey with the Logistic model. The result shows that from the perspective of all the people, farmers are generally lacking eligible collateral; the mortgage loans have reduced the availability of loans to farmers in general while social capital can increase the size of loans in rural areas. From the perspective of the medium to high-income group, the richer farmers are generally able to provide collateral, which helps to raise lending availability. From the perspective of the low-income group, banks are more concerned about the social capital of the farmers, and the function of social capital in loans is bigger than the mortgage; social capital is positively correlated with loan availability. At present, the low-income groups are in the majority in China’s rural areas, to introduce social capital into the farmers’ loan agreements can help farmers to solve the problem of loan difficulty.

Key words: farmers’ loan availability; mortgage loans; social capital