The interferometer includes the optical part and the data acquisition, process and control parts. The optical part includes the laser, the convergent lens, the lens soaked by the solid coated with super resolving power mask arranged in optical axis in sequence along the traveling direction of the laser beam. The part to be measured is positioned above the optical axis and the image lens is in lower part. The data acquisition, process and control parts include the CCD camera, the computer and the displacement controller. The key technique in the invention is the lens soaked by the soild and the mask with supper resolving power. Thus, the smaller pinhole can be obtained as the ideal light source with spherical wave. The position and size of the pinhole are adjustable, providing high transmittance of light and low requirement for the quality of the light beam.