Abstract: Improving life quality has attracted increasing interesting as the ultimate goal and the supreme principle of the social development. Therefore, life quality has been becoming one of the hot issues in many disciplines. In recent years, social capital has been considered as the important factor of life quality and introduced into the life quality research field, which has become the new perception on explaining life satisfaction. It is necessary to discern the impact of social capital on life satisfaction in order to find the measures to improve the living quality. In this paper, life satisfaction was measured with the degree of the farmer's life satisfaction at the present, social capital was measured with informal social network, formal social network, general trust, institution trust and norm, based on the field survey data in Zhangye City, Gannan and Linxia Prefectures of Gansu Province, China using the econometric model to analyze the relationship between social capital and the farmer's life satisfaction. The results indicate as follows:(1)Social capital diversity can be helpful to explain the farmer's life satisfaction diversity,after introducing the social capital index,the models'goodness of fit (R²) increase 0.079-0.088, which clearly proves the social capital is the important factor of the life satisfaction;(2)The relationships between social capital indexes and life satisfaction are in significant positive correlation. Among this, the relationships between the informal social network and life satisfaction, between the general trust and environmental impact and between the institutional trust and environmental impact are all in significant positive correlation, and the regression coefficients are 0.088, 0.032 and 0.093, respectively. That is to say, improving the informal social network, general trust and institutional trust will enhance the life satisfaction, but the change speed of the life satisfaction caused by them is inferior to that of themselves. Both the relationships between the formal social network and life satisfaction, and between norm and life satisfaction are in positive correlation, but they are insignificant in the models;(3)The relationships between income, relative living standard and life satisfaction are in significant positive correlation. Increasing the farmer's income and relative living standard will improve the farmer's life satisfaction. Finally, the paper points out the measures of improving the farmer's life satisfaction and the further concerned problems in the research of the impact of social capital on life satisfaction.

Key words: farmer, social capital, life satisfaction, Gansu