Abstract: The particle size of grinding fineness-0.074 mm accounts for about 75% of a phosphate rock flotation plant in Yunnan. At present, the recovery of flotation collectors used in this plant is low. In order to solve this problem, the research puts forward the adjustment of grinding fineness and the replacement of flotation collector. The grinding fineness-0.074mm adjust accounted for about 80%.At the same time, the use of LX-918L reagent replaces the flotation collectors. Under the appropriate grinding fineness and reagent system, using one roughing flotation, one concentrate flotation and one scavenging flotation, the grade of phosphate concentrate is 31.09%, the recovery of phosphate concentrate is 92.08%, and the grade of magnesium oxide is 0.8%. Compared with the original production index, the grade of Magnesium Oxide in the concentrate was reduced by 12%, the phosphorus grade of tailings was reduced by 1.62%, and the recovery of concentrate was increased by up to 2.81%.