Abstract: Based on the theory of vortex beams and spherical wave interference, an optical measurement method for object micro-displacement was proposed. After improving the Mach-Zehnder interference optical path, a vortex beam was generated as a reference beam, using the spatial light modulator illuminated by a beam of light, and another beam was transformed into a spherical wave through the lens and illuminated to the object. The interference fringes were distributed in a spiral shape as the two beams interfered. When the object has a micro-displacement, the optical path difference of the two beams changes, and the spiral interference fringe rotates. Noticing this phenomenon, the micro-displacement of the object can be determined by the rotation angle of the spiral interference which vortex beams interference with spherical wave. Through theoretical analysis, simulation and experiments have proved that the micro-displacement of the object can be monitored in real time, and effectively calculated by the rotation angle change of spiral fringe based on interference of vortex beams and spherical wave. In the experiment, the displacement of the measured object is 27 nm, the actual measured displacement of the object is 25.75 nm, and the error is 1.25 nm compared with the theoretical value.