The analysis of dynamic characteristics of structures is an important part of seismic design of hydraulic structures. The dynamic response of structures is closely related to their natural vibration characteristics. Therefore, it is necessary to study the natural vibration characteristics of structural systems. In order to better reflect the vibration characteristics of the sluice structure during its operation, this paper takes the Huanhe Landscape Sluice as the research object, establishes two different solid-liquid coupling models of fluid-solid coupling (FSI) and additional mass, extracts the inherent modes of the structure, and extracts the analysis results and the characteristic information based on CEEMDAN-SVD. The results of modal identification are compared. The comparison results show that the finite element model based on FSI theory has better calculation accuracy and modal identification. The results of FSI model are more consistent with CEEMDAN-SVD modal identification results. The maximum error is only 4.12%. The frequency error of the same order is less than that of the additional mass model, and the frequency interval of the adjacent order is relatively stable. It can be seen that the calculation results of the theoretical system model of FSI can more accurately reflect the working characteristics of the sluice structure, and can be better applied to the analysis of the dynamic characteristics of the sluice structure.