A rock specimen, including a rock body having the shape of a cylinder or a regular square prism. The rock body includes: an upper end face, a first circular groove, a first cylinder, a first circular body, a lower end face, a second circular groove, a second cylinder, and a second circular body. The first circular groove is disposed on the upper end face of the rock body and has a circle center coinciding with the center of the upper end face of the rock body. The second circular groove is disposed on the lower end face of the rock body and has a circle center coinciding with the center of the lower end face of the rock body. The outer diameter of the first circular groove is smaller than the inner diameter of the second circular groove, and the first circular groove and the second circular groove are staggered.