Water resources are indispensable materials for the existence and development of mankind.By analyzing the water resources of Yangtze Delta,this paper adopts basic theories of land surface heat and water balance,combines with meteorological,hydrological,soil condition and economy development of Yangtze Delta to develop a calculation and evaluation model of regional water resources amount.It calculates the ground,underground and total water resources of this region.Meanwhile,this paper also develops the sub -models of water consumption system.That is:an agriculture water consumption model based on the agriculture production situation;statistical models for industry and population water consumption based on economic development,population increase etc.Then the models are tested based on actual data.The future situation of water resources' supply and demand balance is predicted and analyzed.It then provides scientific guidance for reasonable use and protection of water resources for this region.