At present, the suspended structure catamaran is composed of the main ship on the water and the side bodies symmetrically distributed on the hull. Such a structure avoids the direct contact of the main ship with the water surface, and has good stability. In this paper, a shock absorption system for ships is designed. It is undertaken by the double wishbone independent suspension system, which includes the upper wishbone, the lower wishbone, the bracket, the shock absorber and other components. The double wishbone suspension system is used in the shock absorption of this project, which can well cope with the huge impact brought by the waves. The 3D model of the hull is modeled, and the external flow field simulation of the catamaran is carried out by using starccm+ software, and the design optimization of the tail structure and thruster is realized.