Abstract: With the development of large-scale hydropower projects, large bridges projects, high-rise building projects, and underground space constructions, how to reasonably determine and select the rock mass mechanical parameters is even more important. The results of selection can directly affect the investment and reliability of the engineering projects. At first, this paper briefly introduces the nature and the concept of the quantile regression. Then, It discusses the backgrounds about the studies of the shear strength of well concrete, the shear strength of simulation crack & chemical grouting concrete dam and the shear strength of concrete with some small cracks in a hydropower station. It further examines the requirements of the relevant specifications with dam design. So, the quantile regression is used to the analysis of the selection of the mechanical parameters. At the same time, the paper uses the linear 0.2 sub-bit value method, the point group center method and the priority given slope method to make various analysis results to be compared. It establishes the advantage of the quantile regression for the two-dimensional mechanical parameters of rock mass. Based on the analysis of the content of the above, the quantile regression is first proposed for the selection of the rock mass mechanics parameters, which will serve the construction as a reference to the analysis of parameters.