Abstract: How to determine the optimal structure of embedded cavities for a given material parameter is a key issue in the design of acoustic coatings. For the decoupled acoustic coatings, an axisymmetric model combined with topology optimization is proposed to find the optimal cavity structure rapidly. In this paper, an axisymmetric simplified model is used to describe the acoustic properties of the periodic acoustic coatings, and the correctness of the finite element model is verified by comparing with the square model, hexagonal model and experimental results. A density-based topology optimization method is used to optimize different regions of the coating. On this basis, a coating structure embedded with the U-shaped cavity is obtained, and the vibration isolation performance is much better than that of a coating typically embedded with cylindrical cavities in the conditions with and without static pressure.