Abstract: This paper discusses the construction of Tianjin's rainwater and flood resource utilization system and its important measures to fully utilize rainwater and flood resources while ensuring flood safety during flood seasons. The system coordinates the water replenishment needs of the city's rivers, wetlands, reservoirs, and ponds through upstream water forecasting and water replenishment demand forecasting, optimizes the allocation of rainwater and flood resources, and realizes routine water replenishment scheduling, water environment scheduling, and water storage scheduling to ensure the water ecological quality of the city's water systems and 36 key control sections. The main functional modules of the system include the main consultation screen, monitoring sub-screen, water storage monitoring, routine water replenishment scheduling, water environment scheduling, water storage scheduling, scheduling management, and statistical analysis. The construction results show that the system can realize the scientific scheduling and coordinated optimization of rainwater and flood resources by integrating the FEDE(forecasting, earli warning, drill, and emergency plan) concept in actual applications. It has good adaptability and operability in different scenarios, and provides important support for the efficient utilization of rainwater and flood resources and water ecological protection in Tianjin.