[Objective] Existing research on digital twin-based urban flood control and drainage dispatch predominantly focuses on forward simulation，while inverse deduction from reservoirs to downstream river networks remains insufficient. This study develops a digital twin platform to conduct scenario simulations across the entire chain from reservoir forward dispatch，inverse calculations for discharge-limited control at downstream sections，to iterative scheme optimization，aiming to provide more precise technical support for urban flood control decision-making. [Methods] Taking Shenzhen Reservoir and its downstream Shenzhen River as the study area，we constructed a coupled hydrological-hydrodynamic model system covering the entire process of rainfall，runoff，dispatch，and evolution. Leveraging the JavaScript engine，hot-reloading，and XML batch processing technologies，the combined simulation workflow was decoupled into standardized functional units. Through the encapsulation of these units，independent configuration and flexible combination of hydrological，hydrodynamic，and dispatch rule models were achieved. Consequently，a digital twin flood dispatch platform for urban reservoirs was developed，featuring robust “forward-inverse-forward” iterative optimization capabilities. [Results and Conclusion] The platform successfully enables forward reservoir dispatch calculations，inverse calculations for discharge-limited control at downstream sections，iterative scheme optimization，and the decoupling and modular batch processing of flood simulation processes. This significantly enhances the operational iteration efficiency of the “forward-inverse-forward” simulation. Future research will introduce parallel computing and reduced-order modeling （ROM） techniques to improve hydraulic response speeds under complex dispatch scenarios.