The invention relates to a magnetic-floating separation technology of micro-fine particle dissemination magnet-hematite mixed ore. The processes of wet-type semi-autogenous grinding, stage grinding, phase-flux weakening-strong magnetism, and strong magnetism concentrate reverse flotation are adopted, the anion reverse flotation operation adopts one-section flotation and roughing, one-section flotation and concentration and a three-section flotation and scavenging ratio closed circuit system to sort flux weakening concentrate and flotation concentrate and combine the flux weakening concentrate and flotation concentrate into the final concentrate, and the grade of the final concentrate is 65-65.5%, and the yield of the final concentrate is 35-40%; one-section strong tailings, two-section strong magnetism tailings and three-section scavenging operation tailings are combined into the final tailings, and the grade of the final tailings is 13-13.5%, and the yield of the final tailings is 60-65%. The magnetic-floating separation technology has the following advantages: the wet-type semi-autogenous grinding process is adopted, the moderate and fine crushing processes are reduced, the cost is decreased, stage grinding and stage separation are realized, magnetic ore is recycled in advance by adopting the single magnetic separation method, 30% of feeding capacity of the flotation operation is reduced, and the chemical dosage is decreased, and the effects of cost decreasing and benefit increasing are realized.