In order to meet the needs of modern warfare, the research on electromagnetic shielding technology of military vehicle-mounted shelters and improving the electromagnetic shielding performance of shelters will play an increasingly important role in the protection of advanced electronic equipment. At the same time, it is also the core of the development of military vehicle-mounted shelters. In this paper, by selecting and comparing different materials, using multi-layer composite materials to design the military vehicle-mounted shelter. The shelter body comprises a front wallboard, a rear wallboard, a left wallboard, a right wallboard, an upper wallboard and a lower wallboard. Each wallboard comprises an outer mask, a sandwich material layer and an inner mask in sequence from outside to inside; the outer masks and the inner masks are all metal shielding slabs or respectively comprise a metal shielding net, and different structures are used for the sandwich layer to construct a multi-layer electromagnetic shielding structure based on material-structure collaborative design, thereby enhancing the electromagnetic shielding effectiveness of military vehicle-mounted shelters. According to the results, multi-layer composite materials show good electromagnetic shielding performance. The shielding effectiveness of the multi-layer shielding material is obviously higher than that of single layer when the shielding layer thickness is smaller than the skin depth, but the increase is not significant after the skin depth is exceeded. In the sandwich layer, the shielding effectiveness of three or more composite shielding materials is no longer significantly increased. The shielding effectiveness increases as the stacking angle increases. When the stacking angle reaches 90°, an orthogonal conductive grid structure is formed. At this time, the electromagnetic shielding performance can be further improved. As the interlayer spacing increases, the shielding effectiveness of the solid metal structure can be slowly improved. However, when the spacing is too large, the orthogonal conductive grid structure of the slatted metal plate is destroyed, and the shielding effectiveness will decrease instead.