Abstract: Based on the controlling effect of rock mass structure on the permeability of rock mass, the percolation media of rock mass are divided into four types, i. e. porous,quasi-porous, planar flow discontinuous and vein flow discontinuous media. The complicated permeability of rock mass I involving inhomogeneous, anisotropic. unsaturated behaviour as well as the coupling between hydraulic conductivity and deformation are discussed. The technical routines for the percolation analysis of rock mass are alsohere.