The co-body design of a sluice and pump station combines the functions of a sluice and a pump station, effectively addressing water flow scheduling issues in the plain river network, while also conserving land resources and improving structural integrity. This paper employs the finite element software ANSYS to analyze the seismic performance of the co-body structure of the sluice and pump station under various peak earthquake accelerations. The analysis aims to verify the structural strength of the co-body design and comprehend the dynamic response of the structure. The results indicate that the displacement stress of the structure meets the code requirements under low peak acceleration. However, the horizontal displacement varies significantly under strong seismic action, leading to potential deformation damage. The tensile stress might exceed the concrete’s tensile strength, requiring measures like increasing the reinforcement rate to ensure the structure’s safe operation. Additionally, the influence of earthquakes increases with the height of the structure, necessitating adjustments in design according to actual requirements. The study’s findings are intended for promoting and referencing the design of the shared body structure of the sluice and pump station.