Abstract: A complex gold bearing copper sulfide ore containing copper，gold and sulfur of 0.82%、1.20 g/t and 11.30%，respectively. The process mineralogy of the copper sulfur ore was studied in detail. According to the characteristics of the ore，the process flow of the principle of preferential flotation of copper and sulfur was applied under low alkalinity，the results of the closed-circuit test indicated that:under the condition of grinding fineness of -74 μm accounting for 85%，CaO as pyrite inhibitor with pulp pH value of 9~10，and Z-200 as copper mineral collector，the copper concentrate with the copper grade of 18.42%，copper recovery rate of 84.97%，gold content of 15.52 g/t and gold recovery rate of 48.78% could be obtained by one roughing，one scavenging and two cleaning copper flotation processes.Then the sulfur concentrate with sulfur grade of 45.42% and sulfur recovery rate of 65.33% could be obtained by the flotation process of one roughing，one scavenging and two cleaning with butyl xanthate as collector after adding pyrite activator QH to the copper tailings.The gold was enriched effectively in the copper concentrate and the comprehensive recovery of valuable metals was realized in the condition of low alkalinity.

Key words: gold bearing copper sulfur ore, low alkalinity, priority flotation for the copper and sulfur, comprehensive recovery