Abstract: This paper inquires into application of random fuzzy method to statistic analysis of mechanical parameters of rock samples and quantitative dividing them into groups of rock mass. The stochastic uncertainty of mechanical parameters of rock samples is discussed. A presented random fuzzy method for processing of experimental data of the mechanical parameters of rock samples is improved. The authors place emphasis on discussion of choice of subjection function of rock samples in this paper. The result indicates that the values obtained with the random fuzzy method is more realistic and better than the conventional methods. Finally, the authors present analytic process: qualitative division of mechanical parameters of rock samples into groups of rock mass statistic computation of them by the random fuzzy method quantitative division of them into groups of rock mass.