Abstract: The raw ore Mo grade of the Molybdenum ore in Heilongjiang Province was 0.062%. Experiments were conducted to test the effect of the fineness of grinding,the dosage of flotation reagent, the time of flotation. According to those results,we conducted two kinds of closed circuit process experiments,and determined the reasonable experiments procedure.in the end,the grade of molybdenum in the concentrate was 49.23%, the recovery rate of molybdenum in the concentrate was 87.98%. This research provided a favorable basis for the geological evaluation and mineral resources development and utilization in this area.