Abstract: Aiming at the problem of excessive copper and lead content in molybdenum concentrate of a large porphyry molybdenum mine in Heilongjiang,the beneficiation optimization test was conducted based on the process mineralogy. The test result showed that the molybdenum concentrate assaying Mo of 54. 32%,Mo recovery rate of 90. 69%,Cu of 0. 048%,Pb of 0. 062% was obtained by using flowsheet of coarse grinding,Mo step flotation,Mo-Cu bulk flotation,Mo-Cu bulk concentrate regrinding and separation of Cu-Mo combined with the self-developed effective molybdenum collector PM for the ores assaying Mo of 0. 122%. Compared to the original process,the copper content in the molybdenum concentrate obtained by the new process had been decreased by 0. 322 percentage points and the lead content had been decreased by 0. 348 percentage points. The process successfully reduced the impurity content of copper and lead in molybdenum concentrate. The research results can provide a basis for the development and utilization of the ore.