Seepage law of fissured rock masses is presented in this paper. The Navier-stokes equation is demonstrated available to describe seepage law of rock masses by testing study. The dynamical seepage pressure in rock masses makes great effect on deformation of rock masses
results in opining of fissure and deformation of rock masses. The seepage and deformation of rock mass and dynamical seepage pressure is studied. The experimental results are checked with Bossiness formula