Wavefront sensing method and device based on point diffraction heterodyne interference of aplanatism unit element

The invention discloses a wavefront sensing method and device based on point diffraction heterodyne interference of an aplanatism unit. The wavefront phase distribution reconstruction method comprises several important steps of optical path debugging, image acquisition, image data processing and target wavefront phase distribution reconstruction. The measuring device comprises a light source placing platform, a light splitting and difference frequency introducing system, a point diffraction filtering system, a unit beam combining system and an image acquisition system. To-be-measured light waves are split into to-be-measured light waves and prepared reference light waves through the light splitting and difference frequency introduction system, the prepared reference light waves are modulated into nearly ideal plane waves through the point diffraction filtering system, finally interference patterns are generated through the unit piece beam combining system, the interference patterns are collected through the i