Abstract: Considering the uneven distribution of snow runoff and precipitation,the catchment is divided into several parts.A water balance model wiich includes the snow storage and snow smelt components is proposed.Using the water balance model,the evey monthly discharge for changing climate conditions have been analyzed and tested.Analyzing the impacts of climate change on hydrology and waer resources in the Manas River Basin.The results indicate:If temperature increase 2℃ and rainf all decrease 20%,then the runoff of summer the runoff of winter the annual runoff will decrease 52.59%,1.77%,46.87%,respectively.