Abstract: The sound stealth for submarine is always a hot spot in research field. Many new sound absorbing materials and structures for this purpose come into use. An analysis of the compound materials applied to the acoustic stealth structure of submarine, especially fiber reinforced plastics in acoustic stealth structure design relating to the material, structure form and sound absorption effect is highlighted. The development trend that sandwich composites used as sound absorbing materials in the submarine structure design is brought forward. By calculating sound reflection and transmission coefficients with variation of the parameters of sandwich layers, the effect of these parameters, such as thickness, sound impedance and sound dissipation, on acoustic properties of sandwich composites is analyzed. The mechanical and acoustic properties of typical and partial structure shell with sandwich composites application are evaluated. The results show that the sandwich composites, applied to replace steel in submarine non-pressure hull, can fulfill the needed strength and rigidity, and its property of acoustic stealth is greatly improved.