Abstract: Based on the fact that the random field of rock and soil mechanical parameters is not always the weak and stationary Gaussian random field,a method combining the geostatistical theory with the three commonly used discretion methods in stochastic finite element is proposed to study the discretion of the random field of rock and soil mechanical parameters.Due to the advantage that the spatial characteristics of random field is acquired from the spatial variation analysis but not from the weak and stationary Gaussian hypothesis,so the discretion of random field is more accurate.