Abstract: This paper presents a stochastic model for rock and soil blending. In the model, the blending ratio, rock size and rock shape can be simulated. The implementation approach of stochastic model is presented. The algorithmic reliability of stochastic model is revealed. Through the statistic analysis, the influence factors on the distribution of stress field in the blending of rock and soil under uniaxial compression are examined, such as the ratio of the blending of rock and soil, the rock size etc. Moreover, the constitutive relation and the strength of rock and soil blending are studied.