A near-eye display system for pupil dilation based on a diffractive optical element, comprising: a laser light source, the laser light source being configured to emit a light beam of tri-primary color wavelengths; a diffusion sheet, arranged on an emergent light path of the laser light source, and configured to obtain a light beam of a predetermined shape by shaping and homogenizing the light beam; a micro-electro-mechanical system (MEMS) scanning mirror, arranged on an emergent light path of the diffusion sheet, and configured to obtain a scanning light beam by scanning the light beam of the predetermined shape at a plurality of angles; a diffractive optical element, arranged on an emergent light path of the MEMS scanning mirror, and configured to divide the scanning light beam into a plurality of beams of scanning light; a collimating lens module, arranged on an emergent light path of the diffractive optical element, and configured to convert the plurality of beams of the scanning light into a plurality of beams of parallel light; a mirror, arranged on an emergent light path of the collimating lens module, and configured to reflect the plurality of beams of parallel light; and a reflective diffraction structure, arranged on a reflection light path of the mirror, and configured to diffract a plurality of beams of reflected light to a human eye, such that the human eye sees a superimposed image of a real world and a virtual world; characterized in that the reflective diffraction structure comprises a substrate and a reflective diffraction layer arranged on the substrate; the reflective diffraction layer being configured to diffract the plurality of beams of reflected light; the substrate being a transparent lens; wherein the diffractive optical element is a dot matrix diffractive optical element; wherein the diffusion sheet is a diffractive optical element structure or a micro lens array structure; wherein the diffractive optical element divides a single light beam into N x M beams of light with equal intensity, wherein N and M are both positive integers. a laser light source, the laser light source being configured to emit a light beam of tri-primary color wavelengths; a diffusion sheet, arranged on an emergent light path of the laser light source, and configured to obtain a light beam of a predetermined shape by shaping and homogenizing the light beam; a micro-electro-mechanical system (MEMS) scanning mirror, arranged on an emergent light path of the diffusion sheet, and configured to obtain a scanning light beam by scanning the light beam of the predetermined shape at a plurality of angles; a diffractive optical element, arranged on an emergent light path of the MEMS scanning mirror, and configured to divide the scanning light beam into a plurality of beams of scanning light; a collimating lens module, arranged on an emergent light path of the diffractive optical element, and configured to convert the plurality of beams of the scanning light into a plurality of beams of parallel light; a mirror, arranged on an emergent light path of the collimating lens module, and configured to reflect the plurality of beams of parallel light; and a reflective diffraction structure, arranged on a reflection light path of the mirror, and configured to diffract a plurality of beams of reflected light to a human eye, such that the human eye sees a superimposed image of a real world and a virtual world; characterized in that the reflective diffraction structure comprises a substrate and a reflective diffraction layer arranged on the substrate; the reflective diffraction layer being configured to diffract the plurality of beams of reflected light; the substrate being a transparent lens; wherein the diffractive optical element is a dot matrix diffractive optical element; wherein the diffusion sheet is a diffractive optical element structure or a micro lens array structure; wherein the diffractive optical element divides a single light beam into N x M beams of light with equal intensity, wherein N and M are both positive integers.