Abstract: The researches on the conical PDC cutter are now focused on numerical simulation, field and laboratory tests, the theoretical analysis on its mechanical properties has not been reported. Therefore, the tensile shear rock breaking mechanism and cutting load distribution characteristics of the conical PDC cutter are described by numerical simulation, the theoretical formula of the cutting load is derived according to the energy balance principle. Results show that comparing with the conventional cylindrical PDC cutter, the rock breaking process of conical PDC cutter is more stable, the cutting load is influenced by the rock properties, the parameters of cutter structure, the cutting depth, and the cutting angle; the cutting load of conical PDC cutter increases with the increase of cone top radius, cutting angle and cutting depth. The research results can provide theoretical support for the design of conical PDC cutter and the PDC bit.