In view of the shortage of water resources and the existing many problems of water price policy in Dianchi Lake Basin, water supply will affect the price of water resources, and then affect the water consumption behavior of residents and industrial enterprises from the perspective of policy simulation. This study proposed a complex system model that coupled multi-agent based models (ABM) and system dynamics (SD) models of watershed water price policy based on the constraint of water resources carrying capacity in Dianchi Lake Basin. The water price policies was simulated and analyzed according to the targets of the 13th Five-Year Plan of water pollution prevention and control in Dianchi Lake Basin. The simulation results indicated that, in the case of the adjustment of comprehensive industrial structure and policy in the Dianchi Lake Basin, in order to achieve the 13th Five-Year Plan targets, the water price of residents and industrial should be raised to 3.23 yuan/m³ and 4.99 yuan/m³, respectively. By speeding up the regulation and control of watershed water price policy, it can effectively guide the residents Agents and enterprises Agents to take water-saving measures and improve their water-using efficiency. It is suggested that the water diversion volume of Dianchi Lake Basin should reduce appropriately to attain 3.06 billion m³. Alternatively, the compensation expense of water diversion can be used for the construction of recycled water facilities. Accordingly, the reuse rates of recycled water should reach to 33% that can be ensured the sustainable utilization of water resources.