Abstract: This is an article in the field of mineral processing engineering. In order to explore the influence of ultrasonic pretreatment on the graphite flotation process of different stages, tests on the effects of different ultrasonic time on the roughing and cleaning of graphite were carried out. The research results show that when the ore contains muddy minerals, ultrasonic pretreatment can’t improve the effect of graphite roughing. Compared with the conventional flotation, the flotation effect of ultrasonic pretreatment for ultrasonic treatment cleaning stage 2, 4 and 6 is gradually improved with the increase of the ultrasonic pretreatment time. When the ultrasonic pretreatment time is 2.5 min, the graphite selection effect is the best. In the test of stage by stage ultrasonic cleaning, the effect of ultrasonic pretreatment for 0.5 min on 1～4 stages is not obvious, but it has a certain effect on 5 and 6 stages. When the ultrasonic pretreatment time is 2.5 min, the effect of each fine section is obvious. The order of the cleaning effect of ultrasonic pretreatment is ultrasonic treatment cleaning stage 5>stage 6>stage 4>stage 3>stage 2>stage 1. The research shows that the flotation effect of ultrasonic pretreatment in the rear section of graphite cleaning is better than that in the front one.