In the context of climate change, the pattern of recreational functions in the Sanjiangyuan region has changed. This paper comprehensively uses the PC (Pairwise Comparison) method, AHP (Analytic Hierarchy Process) method, index model, correlation analysis, and other methods to construct a framework for evaluating recreational functions. On this basis, the change of the three types of recreational function patterns in the Sanjiangyuan region from 1978 to 2012 was traced, and the relationship between this evolution and climate change was examined. Results shows that: (1) factors such as climatic conditions, unique landscapes, vegetation conditions, surface cover, and terrain conditions affect the formation of the recreational function in the Sanjiangyuan region. The different factors play different roles in the procedure of such formation, and these factors have nonlinear contributions. (2) The aesthetic function of the Sanjiangyuan region is stronger, followed by the participation function, and the suitable environment function is the weakest. (3) Climate change has changed the three types of recreational functions in the Sanjiangyuan region to various degrees. Among them, the response of the suitable environment function is the strongest which has been improved, while the response of the participation function is the weakest. The study expands the theory and application of recreational functions, and can help tourism decision-makers of the Sanjiangyuan region towards a sustainable development under climate change.