Abstract: Based on the theory of structural dynamic optimization,the design method for ship pedestal with rigid vibration isolation mass was studied.Within the total weight limits of pressure hull section,two kinds of structural dynamic optimization design models were established with regard to the sectional dimensions and the layout of isolation mass respectively.The target function is average vibration acceleration of pressure hull section.The sectional dimensions and layout of the rigid vibration isolation mass with optimal vibration reduction performance were obtained.The results indicate that the greater the height of isolation mass becomes,the smaller the average vibration acceleration will be.With this model,the optimal design solution satisfied the structural requirement is found and the feasibility of design method is verified.