This study focused on the impact of the scheduling and operation of water-related structures on the flood discharge capacity of the river. We constructed a one-dimensional hydrodynamic model based on the Saint-Venant equations and used the Abbott six implicit finite difference method to approximately solve the equations. The measured cross-sectional data were used for equal-interval interpolation of the model. The water-blocking structures were generalized according to the actual attributes of the structure and the calculation requirements of the model. The model was applied to the Guyuan City section of Qingshui river, where the river conditions were complicated. This model could simulate rather accurately the impact of the rubber dam and water-crossing roads on the flood evolution of the river, and reflected the water-blocking effect of water-blocking structures. The simulation results can be used to check the flood control design standards for rivers, and have certain reference value for the relevant departments to make flood control decisions.