Abstract: The main useful elements are copper and gold of copper gold sulphide ore from Balai County，Lao People′s Democratic Republic.The main copper minerals chalcopyrite and bornite are closely associated symbiosis，crystallization is irregular，the thickness even and grain sizes finer.Pyrite grains are regular，but thickness uneven.Copper sulfide minerals disseminated relatively correlation.Gold mainly exists nakedly or half-nakedly，followed by pattern of gold enwrapped by chalcopyrite.To find the copper selection process，dressing experiment was conducted.The results show that under the condition of grinding fineness -0.074 mm accounting for 70%，lime +YD as sulfur depressor，butyl xanthate as copper collector，via one roughing-two cleaning-two scavenging closed circuit copper flotation process，copper-gold concentrate with 25.08% Cu and 26.00 g/t Ag，copper recovery of 90.78%，gold recovery of 74.12% was obtained.

Key words: Copper gold sulphide ores, Chalcopyrite, Naked or half-naked gold, Copper floatation and sulfur depression