The invention relates to a rock-like material for stress test and its preparation method and application. The rock-like material comprises gypsum layers and carbon nanotube layers, the carbon nanotube layers are interposed among the gypsum layers, and the gypsum layers and the carbon nanotube layers are alternated. The preparation method comprises the following steps: distributing carbon nanotubes in water and polyvinylpyrrolidone to prepare carbon nanotube suspension, adding a gypsum retarder in the carbon nanotube suspension and stirring, and then adding the high strength gypsum to stir to obtain carbon nanotube slurry mixture; adding a gypsum retarder into water and then adding high strength gypsum to produce gypsum slurry; sequentially pouring the gypsum slurry and the carbon nanotube slurry mixture into a mold, and detaching to obtain the material after consolidation. Compared with the prior art, the rock-like material contains the carbon nanotube layers, original nonconductive specimen is changed into locally conductive specimen, and metal spraying do not need to be used because of an electron microscope such that shortcomings of the uneven distribution of the metal layers during gold spraying, influence on sectional microscopic morphology and others shortcomings are avoided.