To meet social and economic development needs of Zhongshan City in the future under conditions of sustainable development and efficient utilization of regional water resources, a system dynamics model was established to simulate the changing trends of economic society, water resources supply and demand, and water environment in Zhongshan City. The entropy weight TOPSIS model was used to analyze the sensitivity of parameters, and comprehensively evaluate the effects of different parameter changes on the water quality, water quantity, and economic society in 2030 and 2040. The results show that under the conventional development mode, the contradiction between supply and demand of water resources in Zhongshan City becomes increasingly prominent, and the deterioration of water environment becomes more serious. Controlling the amount of water consumption has more obvious effect on promoting the regional sustainable development, and the reduction of water consumption of industrial(without including thermal power)added value per ten thousand Yuan has the most significant effect. Different parameter adjustment schemes have different short-term and long-term effects on the water resources system. To make water resources management policies more suitable for long-term development, more attention should be paid to parameter adjustment schemes with obvious long-term effects.