Proper selection of similar materials is the key to the simulation of engineering prototypes. According to the similarity theory of geomechanical model tests, a novel similar material was developed after a great number of mixture ratio tests. The similar material consisted of barite powder and sand as the coarse aggregates, epoxy resin, polyamide, silicone rubber and a silicone rubber curing agent as the adhesive, and gasoline as the solvent. The mechanical tests on this similar material indicated that the material properties were stable and the manufacturing process was simple. Hence, the similar material can meet the requirements of large-scale model tests. The similar material was applied in the model test on a deep-buried tunnel under high in-situ stresses. The deformation and failure process of the tunnel were successfully simulated, and the failure pattern of the tunnel was obtained, which can provide an efficient basis for tunnel design and construction.