Abstract: This paper takes the fine-grained hematite concentrate as the research object. In order to explore the serious overflow loss of the thickening tank in the actual production of thickening and dehydration, the average sedimentation velocity of the clarification layer interface, supernatant turbidity and the unit sedimentation area and other research indicators were used to investigate the effects of fine-grained hematite concentrate feed concentration, flocculant molecular weight, flocculant unit consumption, and flocculant solution concentration on the flocculation and sedimentation of fine-grained hematite concentrate. An experimental study on the influencing factors of flocculation and sedimentation of fine-grained hematite concentrate was designed by designing an orthogonal test. The test results were analyzed with the help of SPSS26 statistical software. The research results show that the order of the influence factors on the average settling velocity is: flocculant unit consumption > flocculant solution concentration > feed concentration > flocculant molecular weight; the order of influence on supernatant turbidity is: flocculant unit consumption > flocculant solution concentration > feed concentration > flocculant molecular weight; the order of the degree of influence on the unit settling area is: flocculant solution concentration > feed concentration > flocculant unit consumption > flocculant molecular weight. Considering comprehensively, the optimal conditions for the flocculation and sedimentation effect of fine-grained hematite concentrate in this experiment are: the molecular weight of the flocculant is 15 million, the feed concentration is 10%, the unit consumption of the flocculant is 60 g/t, and the concentration of the flocculant solution is 0.10%.