Abstract: The nonlinear deformation of rock is caused by heterogeneity and anisotropy.A newly developed numerical code, RFPA (2D) (Rock Failure Process Analysis), is applied to study of failure process of rock under excavating, and macroscopic non-linear behavior of rock may be caused by continually fracturing of micro-element with elastic-brittle character. The reason which causes micro-element continually fracturing (fracturing not at the same time)is the non-homogenous character of micro-element material, such as microelement's strength, elastic modulus and Poisson's ratio, etc.RFPA (2D) is a relative simple compater method on math, but the complication of rock material is considered enough.