Flooding increasingly threatens lives and property under climate change and rapid urbanization. Mobile pumping stations offer a practical and cost-effective solution for flood protection in low-lying, densely populated coastal areas. However, previous studies typically used simplified methods to represent pump stations, and few have integrated pump operations into high-resolution simulations of multi-source urban flooding. This study develops a High-Performance Integrated Hydrodynamic Modeling System–Pumping System Model–Flood Impact Assessment Model (i.e., HiPIMS-PSM-FIM) framework to evaluate object-level exposure and quantify the benefits of pumping. In this framework, the PSM is two-way coupled with HiPIMS using a Source Coupling Method to simulate spatiotemporal flood dynamics. The results are then integrated with exposure data through FIM to identify risks and support mitigation strategies. The framework is applied to a multi-source flood in Yuhuan City, Zhejiang Province, China, at 3 m resolution, and shows strong agreement with field surveys. Vulnerability analysis shows Children > Sedans > Adults > SUVs, with educational facilities facing highest risks. Sensitivity results to pumping rates demonstrate that mobile pumping can reduce the affected population by 82% and decrease impacts on key facilities and roads, demonstrating the framework’s robustness and practical value for enhancing urban flood resilience.