Abstract: By the partial differentiation technique,an iteration procedure for analysis of elastic plastic stochastic finite element method (SFEM) is proposed based on increment theory.Considering the uncertainty of yield criterion,the Drucker Prager criterion is analyzed by probabilistic method,instead of the deterministic method.Corresponding computer program for analysis of elastic plastic SFEM based on probabilistic yield criterion is developed. Two illustrative examples are presented in this paper,and the first numerical example shows that the proposed method yields accurate results compared with the analytical theory results.Second example is a stability analysis of rockmass based on the concept of probabilistic yield criterion,and some probabilistic plastic zones of rockmass corresponding to different levels of target reliability can be obtained by the proposed method.