Abstract: According the viewpoint of the earthquake caused by the faulting,the failure of such saw-cut rock specimens as granodiorite,gabbro and mable was studied under room temperature and confining pressure,σ₂=σ₃= 0.6—1.2kb.During the increase of differential stress,shear strains and fractures started to occur at soft material filling tne saw-cut rock,then the tension crack appeared at the tip of the saw-cut and finally the main rupture,shear/tensile rupture occurred at the same tip nearly parallal to the sawcut strike.Extending tensional cracks were restricted by confining pressure.The distribution of cracks and mechanisms of main ruptrue were influenced by making of the sawcut and properties of rocks.Significance of these results was discussed in the preparation and prediction of the earthquake.