Spatial phase shift Fizeau spherical interferometer

The invention relates to a spatial phase shift Fizeau spherical interferometer, which is characterized in that: the incident surface of a standard lens is plated with a double refraction film and is a plane, and the emergent surface is a spherical surface; the reflection light path of a first beam splitter is provided with a second beam splitter, a second collimation lens, a Dammann grating, an analyzer array, a second image sensor and a computer; a first image sensor is disposed in the reflection light direction of the second beam splitter, so that the spherical surface to be measured can be adjusted conveniently; and the computer is convenient for image data processing. The interferometer can realize profile measurement of measured elements on the spherical surface. The interferometer can obtain multiple phase shift interference images with a certain phase shift quantity. The interferometer uses the circular polarization reference light and the measuring light to reduce influence of residual double refracti