Abstract: With the vigorous development of the new generation of information technologies, the application of digital twin in various industries is also becoming increasingly deep. Faced with the problems of multiple management departments, large spatial scale, variable external environment, and difficulty in joint scheduling in watershed water environment management, this study focused on the comprehensive management projects of the Huangxiao River and Airport River water environment. Based on the five-dimensional digital twin model as the theoretical foundation, and new technologies such as model simulation prediction, BIM, Unreal Engine, etc., a digital twin platform for comprehensive management of the Huangxiao River and Jichang River water environment was established. This platform integrates key information such as weather status, water quality status, abnormal events, and scheduling instructions within the watershed, and constructs a three-level simulation system of "watershed-region-plant and station". It achieves integrated management of "source, plant, pipeline network, river, and lake", providing the managers with intelligent operation and maintenance, predictive warning, dynamic scheduling, and other application values, and achieving real-time and effective supervision and scientific decision-making assistance in water management. It can provide experience and reference for future smart water construction.