Aspheric surface shape interference measuring method and device based on variable compensation lens

The invention discloses an aspheric surface shape interference measuring method based on a variable compensation lens. The method comprises the steps as follows: inserting a variable compensation lens between a point light source formed by a wave-front interferometer and a measured aspheric surface; adjusting the distance between the variable compensation lens and the point light source and the distance between the variable compensation lens and the measured aspheric surface to keep residual aberration compensated by the variable compensation lens within the dynamic measurement range of the wave-front interferometer; and getting the surface shape error of the measured aspheric surface according to the residual aberration compensated by the variable compensation lens. A device comprises a wave-front interferometer and a variable compensation lens. The variable compensation lens is arranged at the front side of a point light source formed by the wave-front interferometer. The axis of the variable compensation lens overlaps with that of the wave-front interferometer. The variable compensation lens is a plane-concave single lens or a plane-convex single lens, and the concave surface of the plane-concave single lens or the convex surface of the plane-convex single lens is a high-order aspheric surface. The method and the device are advantaged in that interference measurement can be performed on a variety of aspheric surface shapes without replacing a compensator.