A 1D-2D coupled hydrodynamic model considering the dynamic infiltration was developed based on the Horton infiltration formula and finite volume method. It was applied in the Zhangwei River system and Daming flood storage-detention area in the Haihe River Basin. The river model was calibrated and verified by using typical floods. At the same time, the influence of infiltration on flood discharge in river, flood diversion in the flood storage-detention area and flood evolution process were discussed. The results show that the river model considering dynamic infiltration has high simulation accuracy, and the peak error of three typical floods is within 10%. River infiltration will obviously delay the start-up time of the flood storage-detention area, and reduce the flood diversion flow and total amount. Infiltration in the flood storage-detention area has little effect on the flood diversion process, but it will accelerate the speed of water withdrawal in the flood storage-detention area.