Abstract: In this paper,the application of fiber reinforced plastics in submarine sound stealth structure is summarized covering the material,structure and sound absorption effect of composites.The develop trend of sound absorbing sandwich composites as submarine structure is brought forward.Then,by calculating sound reflection(α) and transmission coefficients(R)with the variation of the parameters of sandwich layers,the effect of these parameters,such as thickness,sound impedance and sound dissipation,on acoustical properties of sandwich composites is analyzed.At last,the mechanical and acoustical properties of typical and part structural shell is evaluated.The results show that the sandwich composites,applied to replace steel in submarine nonpressure hull,satisfy strength and rigidity requirements and its property of acoustical stealth is much better than that of steel strnctnre.