Abstract: A lead-zinc sulfide is a reworked SEDEX deposit, in which the main gangue mineral is dolomite. About 40%～50% yield of flotation tailing was need to be stockpiled in tailing pond. Due to the inability to expand tailings ponds or build new one, mine production was facing difficulties, so the strategy of full resource utilization was proposed. In this study, the -15+4 mm coarse-grained fraction of the grinding feed was subjected to a dense medium cyclone to separate dolomite. The dolomite product yield was 32.70% and contained 0.043% Pb and 0.16% Zn at the conditions that the specific gravity of the suspension was 2.1 and the pressure of the cyclone was 1.0 kg/cm². The loss rate of lead and zinc was 1.46% and 1.60% respectively. The dolomite product met the dolomite of NBYS19A grade refractory material by chemical analysis. The dolomite product was separated from -15+4 mm particles through the dense medium cyclone, and its resource utilization had been realized, which can reduce 32.70% feed entering the grinding and floatation operation, and can reduce the cost of grinding and floatation. It is of great significance to promote the full resource development of the mine.