Abstract: With the acceleration of urbanization, the water environment problems of urban rivers in Tianjin City have become increasingly prominent. In order to ensure the safety of urban water environment and improve the utilization efficiency of water resources, it is necessary to analyze the hydrodynamic and water quality characteristics of river networks in Tianjin urban areas. Through field investigation in the study area, basic data such as rivers, pipe networks, and pumping stations were collected; on this basis, a non-point source pollution model and a river network hydrodynamic and water quality model are established. The model can simulate the drainage of pumping stations under different rainfall scenarios and the hydrodynamic and water quality processes of different river sections. It reveals the urban non-point source pollution caused by rainfall process and its impact on riverine water quality, and provides technical support for the subsequent improvement of riverine water quality through water diversion in the future.