Abstract: To reveal the rock-breaking mechanism of disc cutters on cone cuttehead of full-face tunnel boring ma? chines (TBM) and verify the influence pattern of the installation arrangement of the disc cutters on the rock-breaking effect, this paper constructs a numerical model of disc cutters on cone cutterhead based on the particle discrete element method, carries out experiments for verification, and conducts a numerical simulation study of the rock-breaking process of disc cutters on cone cutterhead "flat-conical" transition area, based on the analysis of the multi-stage suspension cutting and rock breaking mode of the cone cutterhead. The results show that the rock-breaking of the disc cutters in the conical area is in nature the free-face supported rock-breaking, with the breaking effect jointly influenced by the conical angle of the cutter head, the cutter spacing, and the cutter inclination angle. To improve the rock-breaking efficiency of the cutters, it is advisable to increase the conical angle of the cutter head, reduce the spacing between the cutters in the conical area, and raise the installed angle of the cutters to achieve the "erect in? stallation of oblique cutters" in the conical area. For extremely hard granite with a compressive strength of 180 MPa,the study suggests that the conical angle of the cutter head should be 25°, with the spacing between the cutters in the conical area no more than 70 mm, and the installed inclination of the cutters close to the conical angle of the cutter head.