Abstract: Analyzing and evaluating the impact of the operation and dispatching of hydraulic structures such as sluices and dams on the flood discharge capacity of rivers is helpful to improve their flood discharge efficiency. Taking the Duliujian River as the research object in this paper, the IFMS software was used for modeling, and the measured data during 2023 and 2021 floods were adopted for model calibration and validation. By adjusting the installation and opening and closing of two interception sluices in the model and comparing the water levels upstream of the sluices under the "23·7" flood scenario, the impact of two sluices on the flood carrying capacity of the Duliujian River was analyzed. The results show that the impact of two sluices on the flood carrying capacity of the Duliujian River depends on whether the floodplain between the two interception sluices is flooded or not. Under the scenario of floodplain flooding, the opening of the north interception sluice and the removal of the south interception sluice have a relatively small impact on the flood carrying capacity of the river. Under the scenario of no floodplain flooding, the opening of the north interception sluice and the removal of the south interception sluice can effectively improve the flood carrying efficiency of the Duliujian River.