Abstract: Objective The main metallic minerals in the porphyry copper-molybdenum ore are molybdenite and chalcopyrite. The high mud content has a significant impact on the flotation indicators of the porphyry copper-molybdenum ore. This ore is characterized by high mud content, high secondary copper content, and fine distribution of some Cu-containing minerals. This is also the main reason for the low beneficiation technical indicators of this ore. Method In view of the characteristics of the high mud content secondary copper-molybdenum ore in this area, the processes of mud and sand separation, copper-molybdenum mixed flotation of ore mud, and copper-sulfur mixed flotation of ore sand-regrinding of mixed flotation concentrate are first carried out to eliminate the interference of lime addition in the main process on molybdenum flotation, strengthen the inhibition of ore mud and the selective collection of copper ore, and eliminate the interference of secondary copper. Result The closed-circuit experiment obtained a copper-molybdenum mixed concentrate with a Cu grade of 26.48% and a Mo grade of 0.50%, a Cu recovery rate of 70.84% and a Mo recovery rate of 88.47%, and a copper concentrate with a Cu grade of 17.93% and a Cu recovery rate of 16.48%. Compared with the on-site indicators, the copper concentrate grade increased by 4.13% and the Mo recovery rate increased by 3.55%. Conclusion The application of this process and reagent system effectively avoids the interference of ore sludge on flotation, resolves the impact of lime addition in the main process on the flotation of molybdenum-containing minerals, and while achieving the dissociation of individual copper minerals, effectively prevents copper loss caused by excessive grinding.