As a typical continental river basin of arid areas in Xinjiang, the annual runoff of Manasi river basin mainly comes from the snowmelt runoff in high mountains in the river basin.To know the change rule of runoff in the basin has great significance for probing the relation between atmosphere,hydrology , water resources and ecological environment, and predicting the variation law of runoff.Based on distributed hydrological model EasyDHM(Easy Distributed Hydrological Model), taking Manasi river basin as research objective,the paper used the DEM, river, soil, land use, hydrological and meteorological data to construct Manasi river basin distributed hydrological model to study the runoff process. According to the model test, the accuracy of EasyDHM is higher,the Nash efficiency coefficients of all the stations are above 0.75 during site validation period. It is proved that EasyDHM has good generation capacity and can be applied in analysis of rain situation,and also provide theory for forecasting and relieving the harm of snow-melt flood in spring.