A two-dimensional hydrodynamic model was used to construct a flood routing model for Mengwa flood storage area. The model was verified using remote sensing images, and retrospective simulations of flood routing processes in the flood storage area under three flood diversion scenarios in 2003,2007 and 2020 were performed. The results indicate that the simulated flood inundation results are in good agreement with interpreted remote sensing images, with multiple evaluation indicators above 93%, which verifies the model’s capacity for retrospective simulation of flood diversion scenarios. Flood propagation velocities differ across scenarios; the 2007 flood, characterized by a larger peak discharge and longer duration, arrived at Caotaizi Sluice 8 hours earlier than the 2003 flood. Three flood diversion processes feature distinct patterns:double flood peaks, prolonged high flow, and large peak discharge respectively. Although their flood storage volumes differ greatly, their inundated areas have minor discrepancies, with a maximum difference of only 7.5%. Keywords: two-dimensional hydrodynamics; flood retrospective; remote sensing images; flood inundation; Mengwa flood storage area 〖FL