Abstract: By reviewing Biot′s seepage mechanics theory,this paper discussed physical meaning of coupling seepage equation parameters.According to the basic equation of Biot′s seepage mechanics theory,a coupling equation is added to describe the variety of permeability and porosity.On the basis of elasticity damage equation in RFPA,a new concept of mutation coefficient of permeability is introduced into the equation,a coupling equation of seepage-stress in damage propagation process of rock is brought forward,and a new code of coupling analysis of flow and solid in Rock Failure Process Analysis (F-RFPA 2D ) is developed.The results show that seepage rule and coupling mechanism of seepage and stress in initiation,propagation and evolution of cracks can be simulated by the new code.