Abstract: Hydromechanical coupling of jointed rock mass was the key point for problems of hydraulics of rock mass.In consideration of the deformation of rock mass,the evolution equation of rock permeability coefficient related with volumetric strain and the saturated elasto-plastic damage coupling model were proposed based on the effective stress law of porous media.By means of the nonlinear FEM software ABAQUS,the model was implemented to study the stibility of rock mass and the supporting of the diversion tunnel for Jinping Hydropower Station project during its operation period.It was shown that the hydromechanical coupled model considering evolution of rock permeability coefficient was more realistic to the project,for example,the external water pressures of lining were agreeable to the field measurement.So it was more reasonable than that without considering evolution of permeability coefficient.In the meanwhile,the damage evolution zones did not run through all the areas due to large space between them.