The invention discloses a post-treatment and purification process of iron oxide red for high-property soft magnetic ferrite. The process is characterized by directly water-washing and purifying iron oxide red powder obtained in an acid regeneration process with a Ruthner method, wherein process water is desalted reclaimed water obtained by desalting reclaimed water in a municipal sewage station or is process water obtained by mixing the desalted reclaimed water with production water, and in the water-washing process, the dispersion stability of the iron oxide red particles in a water-based liquid phase is improved by using an ultrasonic dispersion technology and a particle surface modification technology so as to promote the dissolution of soluble impurities in iron oxide red; and then carrying out solid-liquid separation, intensified pneumatic drying and the like. According to the invention, iron oxide red obtained by adopting the post-treatment and purification process disclosed by the invention can meet the production requirement of a high-property soft magnetic ferrite magnetic material. The process has the advantages of short process flow, low energy consumption, no pollution, high yield, stable product property, good consistency of product property and the like, and meets the requirement of industrial mass production.