The invention relates to the technical field of beneficiation of lean hematite, in particular to a new method for flotation, regrinding and re-election, which includes one-stage roughing, one-stage beneficiation, and three-stage sweeping operations, and the concentrate of one-stage roughing operation is fed into The tailings of one stage of selection operation and one stage of roughing operation are fed into one stage of sweeping operation, and the fine tailings of one stage of selected middle ore return to one stage of roughing operation, the concentrate of one stage of concentration operation is flotation concentrate, and the tailings are fed The second-stage sweeping operation, the second-stage sweeping concentrate is returned to the first-stage sweeping operation, the tailings are fed into the third-stage sweeping operation, the third-stage sweeping concentrate is returned to the second-stage sweeping operation, and the first-stage sweeping operation The concentrate is re-grinded to greatly increase the monomer dissociation degree of the concentrate in the first stage of scavenging operation, and the re-grinded product returns to the original flotation process for further separation. Minerals are more fully sorted, which reduces the amount of medium ore circulation in each operation of flotation, and makes the flotation circuit form a virtuous circle. The grade of flotation concentrate is improved, the grade of flotation tailings is reduced, and the metal recovery rate is improved.