Abstract: A porphyry copper-molybdenum ore in Heilongjiang contains 0.410% copper and 0.012% molybdenum. In order to comprehensively recover valuable elements such as copper and molybdenum，the ore dressing test was carried out in view of the characteristics of fine grain size of copper minerals，high content of bornite and high content of mud gangue. The test results show that the copper and molybdenum metals are recovered by copper-molybdenum iso-floatability-enhanced copper flotation recovery and mid‐ dle ore regrinding and reconcentration process. The copper grade of the iso-floatable copper-molybdenum mixed concentrate is 26.24%，the molybdenum grade is 0.71%，and the copper and molybdenum recovery rates are 78.81% and 71.83%，respectively. The copper grade of the enhanced copper flotation concentrate is 15.02%，the molybdenum grade is 0.16%，and the recovery rates of copper and molybdenum are 7.08% and 2.54%，respectively，which effectively improves the concentrate grade and recovery rate.

Key words: porphyry copper-molybdenum deposit, fine distribution, copper molybdenum iso-float‐ ability, enhanced copper flotation, regrinding and resorting of middle ore