In order to explore the NC machining method of spiral groove winding grid structure on conical surface,the parameter equation of the cone equal pitch spiral line was studied.Through coordinate transformation,the machining tool positions of spiral groove were deduced.Finally,the NC machining of the spiral groove with equal pitch on the surface of the cone with a constant blade angle was realized on the three-axis linkage machine bed.The research results show that the verticality of the side wall and bottom of the spiral groove reaches 0.02 mm,the surface roughness reaches Ra 1.6 μm ,and the depth of the groove is 6 ~ 6.03 mm.Compared with the five-axis processing,it is a remarkable improvement.In addition,the processing efficiency is doubled and the cost is reduced by 68%.This method should be promoted and applied in engineering.