Abstract: In order to analyze the effects of climate change on evaporation of reservoirs in Yarkant River Basin, the statistical downscaling model with temperature, relative humidity and wind speed as the three main factors was established based on BP artificial neural network. The evaporation was predicted and the changes of evaporation of reservoirs in 2020s, 2050s and 2080s were analyzed under 3 scenarios of global climate model BCC-CSM1.1. The result shows that the evaporation of reservoirs in the basin as a whole is in increasing trend and follows the order of RCP8.5, RCP 4.5 and RCP2.6. Under the three scenarios, the evaporation in 2020s ranges from 1922.4mm to 2337.9mm and the loss ratio of evaporation and seepage ranges from 35.17% to 36.40%.