Abstract: Rock mechanical characteristic is basic issue in the study of rock engineering. Rock mechanical characteristic is very complex because of the rock composition's non-homogeneous and the structure's complexity. It is affected by many factors. Basic on the study of experiments, the quantitative analysis of lithological characteristic index about rocksalt and other rocks is carried out by the dimension theory, matrix theory and the knowledge of rock mechanics in this paper. And the effect of lithological characteristic index to rock mechanical properties are also discussed. The results indicates that the ratio between the tensile strength and the compressive strength will be larger along with the accretion of the anhydrite 's contents in the rock under natural station of containing water. The tangent module, Poisson 's ratio, one-dimensional compressive strength and cohesion are all will be larger along with the accretion of calcite contents and cranny 's length-ratio in the rock.