Abstract: For a deeper understanding of the mechanism of rock failure, the failure loads of two groups of 24 cylindrical rock samples were measured by pressure and shear tests. Using a high precision 3D laser scanner to scan the fracture surface of the rock sample, the characteristics of fracture surface roughness distribution are respectively obtained after the compression failure and shear failure. The radius of curvature of cross section curve is obtained using statistical analysis. It reveals the correlation relationship between the curvature radius and roughness coefficient JRC, and the failure load of sandstone, respectively. The results show that the farther away from the load center, the smaller the JRC in uniaxial compression test. The curvature radius of the roughness curve has a linear positive correlation with JRC and the shear strength in the shear test.