The invention relates to a milling and processing method of a spiral surface of a ring surface worm, belonging to a processing method of a ring surface worm. The ring surface worm (1), a cylinder milling cutter (2), a worm axial line (3), a milling cutter axial line (4), a tool holder axial line (5) vertical to the worm axial line (3) in a staggering way and a common perpendicular (6) of two axial lines are provided in the technical scheme, wherein intersecting points are respectively O and O', the milling cutter axial line (4) rotates around the tool holder axial line (5) through the point O', and a series of corresponding points of a left spiral surface and a right spiral surface on different axial sections when a ring surface radius of a corresponding center distance from a0 to a of a spiral groove of the ring surface worm (1) is Rd are obtained based on a forming principle of the ring surface worm (1) so that a front end circle of the cylinder milling cutter (2) is respectively incontact with and tangential to the left spiral surface and the right spiral surface of the spiral groove of the ring surface worm (1) on the series of corresponding points. The spiral groove and the spiral surface of the ring surface worm (1) are milled in a laminating way along the tangential direction and the radial direction of a ring surface from a meshing in end and a meshing out end. The invention provides a new method for processing various ring surface worms.