Abstract: The high secondary copper and slime content in a copper-molybdenum mixed concentrate makes the secondary copper mineral difficult to inhibit during copper-molybdenum separation flotation and the produced copper-molybdenum concentrates fail to meet the quality requirement. So the pre-separation-copper and molybdenum separation process is studied. The results show that when the copper grade is 24.40 % and molybdenum grade is 0.46 % in the copper-molybdenum mixed concentrate and the test conditions are optimum， the flotation process that includes pre-separation， one roughing， twice scavenging， eight times cleaning and middling recycling， can obtain the molybdenum concentrate with molybdenum grade 51.56 %， copper grade 1.05 % and molybdenum recovery rate 74.29 %， and the copper concentrate with copper grade 24.55 %， molybdenum grade 0.12 % and copper recovery rate 99.97 %. The new process achieves effective separation of copper and molybdenum for an easily argillizable copper-molybdenum mixed concentrate with high secondary copper content.