Abstract: Climate change impacts on temporal and spatial patterns of water resources and assessment of this impact is important. To study runoff responses to climate change, we developed a distributed hydrological model of the Qinglong River watershed on the platform of Soil and Water Assessment Tool (SWAT), accounting for digital elevation models of the watershed and its data of land use, soil types, etc. A sequential uncertainty fitting version 2 (SUFI2) algorithm in SWAT-CUP software was used for sensitivity analysis, calibration, validation, and uncertainty analysis, including sensitivity analysis on the t-Stat and p-Values and model evaluation in terms of efficiency coefficient Ens and its correlation coefficient R2, Pfactor, and Rfactor. The results indicate that this model based SWAT is applicable to river watershed runoff modeling. In its application to simulations of the river runoff in different level years, hypothetical schemes of climate change were designed by combinations of precipitation and temperature conditions. Simulations show a significant influence of climate change on runoff. The runoff is increased by an increase in precipitation or air temperature and it is more sensitive to precipitation.