Abstract: Utilizing the longitudinal box girder deck structure of Germany F124 frigate as a study case,the strength deck deformations under non-contact explosion were calculated by the fluid-structure coupling method.Ultimate bearing capacities of box girder and ordinary warship compartment structure with plastic deformation damage under various impact factors were compared and analyzed by the damping factor method.The results indicate that under non-contact explosion,compared with ordinary deck structure,box girder structure is more advanced with smaller deformation and slower decreasing of ultimate bearing capacity after deformation,so that it can sign ificantly improve the survivability of warship.