Seepage tests under different loading and unloading confining pressures and different hydraulic gradients are conducted on single granite fracture to study the effects of stress history on fracture permeability evolution. Experimental results show that during loading process

flowrate is approximately linear with hydraulic gradient; under the same hydraulic gradient

flowrate decreases with the increase of confining pressure at a step-down rate

but with further increase of confining pressure

the reducing amplitude of the flow becomes smaller and smaller. Under the same confining pressure and hydraulic gradient

the flowrate of the single granite fracture deceases obviously during unloading process compared with that during loading process. Furthermore

flowrate is no longer linear with hydraulic gradient during the unloading process of confining pressure. Comparison between roughness coefficients before and after test shows that

joint roughness coefficient(JRC) of the fracture after test decreases dramatically due to the normal compression and scouring of the seepage fluid. Obvious hysteresis of fracture permeability recovering is also observed

indicating inelastic deformation of the fracture occurs under combined effects of normal stress and fluid scouring.