Abstract: With the intensification of climate change and human activities, water resources in the basin are more and more affected by the changing environment. It is of great significance to study the change characteristics of watershed water resources system and water demand prediction in the changing environment to support the management and rational allocation of watershed water resources. Based on the principle of system dynamics, coupled with the water demand prediction method considering physical mechanism, this article establishes the model of water resources system. Taking the Yellow River basin as an example, this paper analyzes the change characteristics of water resources system in the Yellow River basin under the action of multi-factor driving and multi-element stress, and predicts the evolution trend of water resources supply and demand in the Yellow River basin from 2017 to 2030 according to five different economic and social development situations in the future basin and the predicted future temperature and precipitation results using MPI climate model. The results show that: (1) The domestic water demand of the Yellow River basin increases continuously with the increase of the population and the per capita water demand of the basin. With the adjustment of industrial structure, the water demand for industry shows a trend of slow decrease, while the water demand for ecology and production increases year by year. (2) On the premise of strengthening the river basin water resources management and increasing the investment in water-saving technology, we should ensure the coordinated development of the basin economy and society, pay attention to the development of the economy while giving consideration to ecological environment protection in the basin, and meet the requirements of sustainable economic and social development in the next stage of the Yellow River basin. (3) In order to ensure the sustainable development of water resources in the Yellow River basin, and realize the ecological protection and high-quality development of the Yellow River basin, it is necessary to adjust the strategies of water resources management in the basin, improve the degree of water-saving, and promote the optimization of the industrial structure of the basin.