Abstract: Cutting parameters and physical characteristics of fractures rock mass are important factors influencing the rock-breaking mechanism of roller cutters under hard rock conditions.The discrete fracture network (DFN) model,the rough discrete fractures network (RDFN) model,and the three-dimensional square rolling cutter model were established based on MATLAB and AutoCAD.The Particle Flow Code (PFC) simulation was conducted to analyze the rock-breaking effect of different rock invasion speeds and surface roughness.The results indicate that the intact rock roller breaks the rock,the failure zone gradually extends from the rock surface to the interior,and the force chain shows a divergent distribution.The speed of the rolling cutter has no significant impact on the change in the failure load and the number of cracks,both of which are primarily shear cracks.Rock breaking of the rock mass with complex fractured surfaces,and the force chain and crack extension were distributed along the fracture surface,mainly with tensile cracks.The failure zone was formed by gradually penetrating the rock surface from the initial failure fracture surface.The failure load of the RDFN model was larger than that of the DFN model.The fracture surfaces controlled the crack propagation and failure modes of RDFN and DFN models.The crack propagation direction was affected by the surface roughness.The research results can provide useful references for similar practical engineering rock mass rock-breaking.