Abstract: The credit as one of the important issues in the field of economic development has been taken much of the attention of experts and scholars. In recent years，many experts and scholars found that social capital has important implications on the credit behavior. Credit constraints has become a common phenomenon in rural areas in developing countries，no more than 27% of rural households in China has access to formal channels of loans，but about 40% the farmers’ loan demand cannot get formal loan support，therefore，the majority of farmers has turned to private loans. A large number of studies has found that social capital has a significant effect on credit behavior and private credit. Therefore，to play the role of social capital，the contact between credit institutions and farmers closely becomes an important means to solve farmers’ credit constraints. Based on this，this paper takes the farmers of Gannan Tibetan Autonomous Prefecture（GTAP），Linxia Hui Autonomous Prefecture（LHAP） and Zhangye City（ZC） of Gansu Province，China as the examples，based on the household survey data and the index system of social capital established on the framework proposed by Robert D. Putnam，using the factor analysis to analyze the social capital of different ethnic groups. Then the hypotheses of the social capital that have a positive effect on farmers’ credit behavior is formulated，using binary logistic regression model，this paper analyzes the social capital and other factors on the influence of the credit behavior. And using the maximum likelihood estimation method to estimate their regression parameters，its aim is to provide references for improvement of the credit mechanism，the advancement of rural financial reform，and the development of the rural economy. The results showed as follows：（1） The lowest total score of social capital of GTAP is 0.91，the total score of LHAP is 1.20，the highest total score of Zhangye  City is 1.26. （2）From each dimension of social capital，the　trust，network and norms have positive correlation with credit behavior incidence. （3）The human capital，physical capital and financial capital have a positive impact on the credit behavior incidence，and the natural capital haｓ the negative effect on the incidence of credit behavior. The innovation of this paper is to analyze the influence of the social capital on credit behavior of famers in different countries.

Key words: social capital, credit, Gannan Tibetan Autonomous Prefecture（GTAP）, Linxia Hui Autonomous Prefecture（LHAP）, Zhangye City（ZC）, Farmers