Drought is one of the scientific issues of concern in the context of global climate change, it not only affects the agricultural production, threatens farmers'livelihoods,and even restricts the rural sustainable development. It can help us to improve farmers'livelihood sustainability to study farmers'adaptive capability against drought. In this paper,a case study on farmer's adaptive capability against drought in Yuzhong County in central Gansu Province was carried out,and an evaluation model was established by means of concept of the social-ecological system framework ( SES) . Based on the surveyed data of farmers'livelihood situation, the farmers were divided into the subsidy-dependent,agricultural-oriented, industrial-oriented,by-business and professional types, the adaptive capability of rural farmers in Yuzhong County was quantitatively assessed,and the factors affecting farmers'adaptive capability were analyzed. The results showed that: ① The types of farmers were diversification,among them the proportion of industrial-oriented farmers was the highest,and that of professional farmers was the lowest; ② The overall stability of farmers'adaptive capability against drought was poor,and there was a significant internal difference. The stability of types of farmers'adaptive capability against drought was in an order of subsidy-dependent type > agricultural- oriented type > industrial-oriented type > by-business type > professional type; ③ The factors restricting farmers'adaptive capability against drought were mainly the drought loss,natural capital, farmers'cognition,watersaving irrigation and social capital.