The structure for a water resources system and water demand is analyzed. Coupled modeling methods for surface and groundwater are studied. The objective management model of water resources is established. The optimization management for water resources in the Dushanzi area is carried out. The results show that water resources in the Dushanzi area can meet the demand of water supply for Dushanzi and irrigation for the area under the current situation. However, for the short-term, middle-term, and long-term plans, the water demand cannot be met even though the four water source areas work together. Some external water resources are needed. Overall, even with external water resources, the water saving measures need to be implemented and the irrigation efficiency needs to be improved.