Aiming at the design for distribution layer in defense works, attenuation mechanism and evolution law of stress waves in distribution layer with cylindrical shells were focused on. It was found that dispersion and diffraction effect of stress waves were occurred in the concrete medium on the basis of theoretical analysis and numerical simulations, which significantly weakened the strength of stress waves behind the shells. The position、interlayer spacing and the arrangement forms of the shells had great influence on the protection performance of the structures. The results show: in the structures with single-layer cylindrical shells, the smaller the space between the shells and the protected area is, the better the protection performance is; in the structure with two-layer cylindrical shells, the smaller the interlayer spacing is, the better the protection performance is, and the protection performance of the stagger structure is better than that of the aligned structure.