Regional water balance analysis is the foundation that will guarantee the sustainable and scientific use of water resources and the sustainable development of the economy.In this study

the CPSP hydrological model is selected as the regional waterbalance analysis tool for Daxing District.The model is validated with the 3 types of data as the runoff data from the Integrated Planning of Water Resource in Daxing District of Beijing

the evapotranspiration data estimated by remote sensing-based model（RS-ET）

and the groundwater monitoring data

respectively.The calculated runoff data are basically consistent with that of the Integrated Planning of Water Resource in Daxing District

Beijing.Meantime the dynamic variation of evapotranspiration（ET） and groundwater reserves are better simulated by the CPSP hydrological model.Serving as the basis for this study

the current water resources for 2004 and 2005 are evaluated

in which the water shortages are 0.72×108 m3 and 1.80×108 m3

respectively.