Since the terrorist attacks have increased over the world in recent years, blast-resistant protection of building structures has received considerable attention. The rigid and flexible composite protection layer as a new protection measure was examined through the method of experimental tests in this paper. Two sealed steel boxes were selected for the testing, one with the rigid and flexible composite layer, while the other without any protection. The rubber was selected as the flexible material while the steel plate is selected as the rigid material. The effectiveness of the composite layer under different explosive loadings was investigated. By comparing the structural strains, the experimental results show that the rigid and flexible layer can suppress the structural dynamic response obviously, and the blast-resistant effect of the composite layer will be increased further with increase of explosive charge.