Abstract: In this paper, simulations and experiments of the multi-base acoustic scattering characteristics of thin-shell targets in water are carried out. Firstly, two different numerical calculation methods, finite element coupled with boundary element method and Kirchhoff approximate integration method, are used to simulate the multi-base acoustic scattering characteristics of the cylindrical shell with an internally inflated spherical crown, and the validity of the simulation results is verified by experimental measurements in an anechoic pool. The same numerical calculation method is used to simulate the multi-base scattered sound field of Benchmark model and analyze the corresponding omnidirectional sound scattering characteristics and scattering mechanism. The results show that the echo intensity and the echo structure of multi-base scattering from underwater targets are related to the multi-base split angle, and the width of the main flap of the echo bright spot also varies with the multi-base split angle; there is a strong interference effect between the hull and the command module of the Benchmark model, which tilts the vertical stripes of the multi-base scattered sound field in all directions. The study provides theoretical support for the multi-base detection of underwater targets.