The invention discloses a method for
machining an off-axis aspherical mirror. The method comprises the steps that 1, a rotary aspherical matrix structure is designed; 2, a through hole for inlaying of a
daughter structure is excavated in a matrix blank; 3, a cylindrical integral workpiece is formed by combining a matrix and a
daughter; 4, an initial spherical surface is machined; 5,
grinding is guided through the
surface shape error detecting result of a contourgraph, and the
surface shape error between the initial spherical surface and a rotary aspheric surface is corrected; and 6,
polishing is guided through the
surface shape error detecting result of an interferometer or knife-edge tester, and the off-axis aspherical
daughter is taken out after
polishing is completed. The method is characterized in that the
caliber D of the initial spherical surface is equal to the
diameter of a cylinder of the integral workpiece, and the curvature
radius R of the initial spherical surface is equal to the
radius of a circumcircle of a triangle formed by a vertex in a rotary aspheric
bus equation and a first point and a second point which are located at the position with the
caliber of 1.414 D on a rotary aspheric
bus. According to the method, the problem of the influence of the fringe effect in the prior art is solved, the efficiency of aspherical surface
machining is improved, and
machining difficulty is reduced.