Abstract: The Beijing-Tianjin-Hebei Urban Agglomeration is a serious water shortage area, so scientific and reasonable prediction of its water demand is the premise and foundation for the water department to plan and construct future water supply projects.A prediction study was conducted on the water demand of the Beijing-Tianjin-Hebei Urban Agglomeration.Explanatory variables related to economy, society, water use and resource availability were identified.Based on the data of the Beijing-Tianjin-Hebei Urban Agglomeration from 2004 to 2020,six machine learning models were established to seek the optimal prediction model.The water supply data was also collected and analyzed to further measure the difference between water supply and demand in 2021～2025.The results show that XGBoost model has the best performance and the lowest error, and the prediction accuracy is 99.98%.It is predicted that the average annual water demand of the Beijing-Tianjin-Hebei Urban Agglomeration from 2021 to 2025 will decrease slightly compared with previous years, fluctuating at around 25.06 billion m3.The total gap between supply and demand of water supply projects in 2021～2025 is expected to be about 600 million m3.In view of the planning and construction of water supply projects in the Beijing-Tianjin-Hebei Urban Agglomeration, it is suggested to carry out the planning from the following aspects, continuously promoting the construction of South-to-North Water Diversion Project, coordinating the construction of green water-saving cities and continuously optimizing the construction of water supply network in the urban agglomeration.