Abstract: Based on similar principle of the geomechanical model test,the ratio of similar material gypsum were targeted tested.The similar material gypsum is mainly constituted by gypsum powder,quartz sand,cement,polypropylene fiber,and water.Specimen is made in accordance with the provisions of the ratio,uniform mixing and then is stripped by compaction.Uniaxial compressive strength tests and direct shear tests are made with the standard test specimen for obtaining mechanical parameters of the similar materials.Exploring the influence of each chemical composition on σ_c、γ and E.The purpose is electing suitable ratio value for large-scale geomechanical model test and preparing for a one-time casting size model specimen.Similar material gypsum has the character of severe adjustable,wide range of mechanical parameters,stable performance,low price,quick drying,simple fabrication process and non-toxic harmless.