A vortex beam-excited precision grating displacement measurement apparatus, which performs displacement measurement by taking a vortex beam carrying topological charges as an excitation light source of a grating and by using the interference of a ±m-order diffracted vortex beam. In the vortex beam-excited precision grating displacement measurement method and apparatus, the displacement p/m of the measured displacement corresponds to the rotation of a circle 2π rad of an interference petal pattern, and then the rotation of 1° of the interference petal pattern corresponds to the measured displacement amount of p/360m. Compared with a conventional grating measurement method, the present disclosure provides a grating interference sensing signal that realizes a higher optical subdivision rate itself.