In view of the difficulty and low efficiency of fine hematite flotation,nanobubbles with special interfacial properties were applied to reverse the flotation of hematite to improve the flotation behavior and separation performance of fine particles.The Box-Behnken response surface method was used to design the experiments and optimize the reagent dosage for reverse nanobubble flotation of hematite from the flotation feed at Anqian Mineral Processing Plant by specifically analyzing the effect of each factor and the interactions between factors on the flotation performance.The results show that collector TD-Ⅱ and corn starch had more significant impacts on grade and recovery than lime and the interactions between starch,lime,and collector TD-Ⅱ had significant effects on iron grade.The iron recovery is 82.27 % and the iron grade is 67.32 % for the concentrate when 3.0 kg/t corn starch,1.5 kg/t lime,and 0.78 kg/t collector TD-Ⅱ are added.The application of the nanobubble flotation process will help resolve the difficulty in the efficient flotation of fine particles,which is of great significance to improving the technical performance indicators and economic benefits of the mineral processing plant.