To investigate the impact of diesel microemulsion on the flotation effectiveness of a fine flake graphite mine in Luobei area, the diesel microemulsion was prepared by high-speed stirring method, with Span 80 and Tween 80 as emulsifiers, n-butanol as co-emulsifier and diesel oil at the mass ratio of 2∶1∶1, and the flotation effect was analyzed. The results show that: Using the traditional graphite beneficiation process of stage grinding and flotation, and comparing the rough concentrate flotation tests with diesel and diesel microemulsion as collectors, when the same concentrate recovery rate is obtained, the oil-saving rates of diesel microemulsion are 25.11% and 50.43%, respectively. In the open-circuit experiments, the oil-saving rate of diesel microemulsion is 28.83%. Therefore, the flotation performance of diesel microemulsion is significantly better than that of diesel. In the standing time flotation test, the diesel microemulsion can be stored for at least 40 d, and the microemulsion has good stability, which can solve the problem of drug storage in industrial production. Among the economic benefits, the cost of collector of diesel microemulsion required for selecting 1 t of graphite is only 81.91% of that of diesel. Diesel microemulsion can not only improve the flotation index of fine flake graphite, but also reduce the dosage of collector and the cost of reagents used for flotation.