The critical slip surface of a fractured rock slope tends to extend along the fractures.Thus,fracture orientation plays a critical role in determining the critical slip surface.Based on fracture orientation data,this paper examines the critical slip surfaces of fractured rock slopes.Given that the surface of a fractured rock slope extends along the fracture surfaces,or the wedges,with each composed of two arbitrary fractures,the critical slip surface is determined via stochastic dynamics.In addition,a fracture frequency method is proposed as a means of analyzing the critical slip surface.According to this method,the critical slip surface slips in whichever direction has the lowest fracture frequency.Based on the stochastic dynamics method and the fracture frequency method,the critical slip surface of the slope is finally determined,that is,the critical slip surface takes the form of a plane passing the slope toe with a dip of 120° and a dip angle of 45°. The critical slip surface of a fractured rock slope tends to extend along the fractures.Thus, the critical role of determining the critical slip surface.Based on fracture orientation data, this paper examines the critical slip surfaces of fractured rock slopes.Given that the surface of a fractured rock slope extends along the fracture surfaces, or the wedges, with each composed of two arbitrary fractures, the critical slip surface is determined via stochastic dynamics.In addition, a fracture frequency method is proposed as a means of analyzing the critical slip surface. Accord to this method, the critical slip surface slips in whichever direction has the fracture frequency method, the critical slip surface of the slope is finally determined, that is, the critical slip surface takes the form of a plane passing the slope toe with a dip of 120 ° and a dip angle of 45 °.