The similar scale model experiment can provide some reference for the research and development of naval gun weapons. This paper takes the naval gun bracket as an example to explain. Based on the dimensional analysis, equation analysis and finite element method, the modal parameter similarity relationship between the original model for bracket and the shrinkage ratio model is established. The results show that the error of predicting the natural frequency of the original model based on

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... relation is less than 2% comparing with the results of finite element numerical simulation, and the error is less than 10% comparing with the experimental results, and the mode of shrinkage model is close to that of the original model. It is proved that the theoretical method in this paper is feasible and practical in engineering. Therefore, the vibration characteristics of the original model can be estimated by analyzing the vibration characteristics of the carrier shrinkage ratio model, which provides a reference for ship gun designers.