Abstract: The porphyry copper-molybdenum ore has the characteristics of complex ore distribution, fine disseminated grain size, and similar floatability of molybdenite and chalcopyrite, which lead to the difficulty of copper and molybdenum separation in the flotation process. On the basis of the unique characteristics that ultrasound can change the properties of pulp, mineral surfaces and pharmaceutical solutions, ultrasonic technology was used to dedrug copper and molybdenum ore to strengthen the flotation separation of copper and molybdenum. Research on pure mineral flotation shows that the separation of chalcopyite and molybdenite can be effectively realized by ultrasonic treatment. The actual ore separation shows that the mixed copper-molybdenum concentrate has better indexes when the grinding concentration is 66.7%, pulp pH =10.0, lime dosage 450 g/t, sodium silicate 1 kg/t, YC agent + butyl xanthate dosage 160 g/t+50 g/t, 2# oil 30 g/t and grinding fineness (-0.074 mm) 77.2%. At this time, in the mixed copper-molybdenum concentrate, the grade of molybdenum is 2.96% with a recovery of 87.44%, and the grade of copper is 0.76% with a recovery of 92.77%. Ultrasonic pretreatment with a power of 2 000 W was conducted on the mixed copper-molybdenum concentrate for 20 min at a 10% pulp concentration. The flotation conditions were pulp pH=10, kerosene dosage 80 g/t, 2^# oil dosage 15 g/t and sodium sulfide dosage 300 g/t. In the final molybdenum concentrate, the Mo grade was 22.19%, with a recovery of 95.95% and a total molybdenum recovery of 83.90%. In the copper concentrate, the copper grade is 11.88% with a recovery of 98.27% and a total copper recovery of 91.16%. The separation of copper and molybdenum is well carried out.