The invention discloses Particle granularity measuring equipment based on a Mie scattering theory, which particularly relates to the field of particle granularity measurement methods. The equipment comprises a parallel light generation module, a sample dispersion module, a light scattering acquisition module, an electric control two-dimensional guide table and a data processing module, wherein theparallel light generation module, the sample dispersion module and the light scattering acquisition module are distributed in a line from left to right. The area array CCD is used as a receiving device, anAiry disk image is obtained, the position information is extracted, image guide centering is realized, a centering correction parameter is solved, and the accuracy of a measurement result is improved; the position of the area array CCD is controlled by designing a two-dimensional guide table,a plurality of images at different positions are shot, an image splicing technology is utilized, a large-angle light scattering energy diagram is collected, an image processing method is utilized, scattering angles are dynamically divided, the resolution of granularity measurement is improved, a neural network principle is utilized, a traditional inversion algorithm is improved, and the accuracy, speed and reliability of the algorithm are improved.