Abstract: The Isa mill has simple process, covering a small area, with less capital investment, convenient operation and easy to maintenance. The raw material for a lepidolite beneficiation in Yichun, Jiangxi Province, is tantalum niobium tailings. Most of the lepidolite ores belongs to fine-grained embedded type, which is usually associated or coexisted with gangue minerals such as quartz and feldspar and easy to produce sliming, which will affect the subsequent flotation. To this end, a new type of fine grinding equipment, Isa mill, instead of ball mill was carried out to improve the flotation index of lepidolite. The results show that Isa mill is used as the open-circuit grin equipment, the fineness of the product is less than or equal to ≤0.074 mm, accounting for 60%, which simply and efficiently meets the requirements of the dissociation degree of lepidolite flotation mineral particles. Using CY205 as collector, WST as inhibitor and adopting the separation process of "one roughing, three cleaning and three scavenging", lepidolite concentrate product with Li2O grade of 5.15% and recovery rate of 77.80% can be obtained in the laboratory. The results would have a certain promotion and reference significance for the practical application of Isa mill in dressing plant.