Due to the influence of dispersion error and element dispersion, the computational efficiency and accuracy of the traditional finite element method are poor in the analysis of middle and high frequency acoustic-vibration coupling characteristics of the elastic cavity. In this paper, the acoustic field model of the cavity was established by the edge smoothing finite element method, and the viscoelastic material was simulated by the GHM model. Considering the multi-field coupling between the elastic cavity, the structure of the CLD and the acoustic field in the cavity, a numerical model of the two-dimensional CLD elastic cavity was found, and the acoustic vibration coupling characteristics of the composite cavity were analyzed. Numerical examples show that the computational accuracy of the hybrid finite element model is equivalent to that of the traditional finite element model in the low frequency range, while the computational accuracy and stability of the proposed model are superior to that of the traditional finite element method in the middle and high frequency range.