Abstract: Based on the design of warship＇s strength deck structure and contact explosion conditions,nu-merical simulations were carried out by introducing nonlinear element method under distinct combinations of contact explos ion charges,girder and beam sizes of the strength deck.The air shock wave pressure distribution and the impact on strength deck under ball explosive contact blast were analyzed.The results show that there are three fai lure modes of strength deck structure under contact explosion,the research proposes criteria for failure modes through defining the relative strength factors of girder and beam,which can preliminarily describe the plas tic dynamic response characteristics of strength deck under con-tact explosion.