Abstract: A porphyry copper ore in Yunnan has a copper grade of 0.34% and an associated recoverable molybdenum grade of 0.015%, belonging to a typical low−grade associated mineral resource with significant comprehensive recovery value. Currently, this mine is confronted with two key technical challenges: first, copper minerals are prone to loss in fine−grained fractions, which impairs metal recovery rate; second, the continuous increase in fine mud not only disturbs the stability of the flotation system but also directly reduces the concentrate grade, seriously restricting the improvement of the technical and economic indicators of the concentrator.Under the original reagent system, the closed−circuit test achieved copper concentrate grade of 21.06%, molybdenum concentrate grade of 0.67%, copper recovery rate of 83.10% and molybdenum recovery rate of 59.93% respectively. To further break through the production bottleneck without changing the existing process flow of the plant, process mineralogy analysis was conducted to clarify the dissemination characteristics and particle size of copper and molybdenum minerals in the ore, providing a theoretical basis for subsequent process optimization. Meanwhile, the effects of grinding fineness, pH value, frother and collector on the recovery efficiency of copper and molybdenum were investigated, and the reagent system was further optimized by adopting the high−efficiency composite ester reagent BK335 developed by China National Mining and Metallurgy Group.The results of copper−molybdenum bulk flotation tests show that using BK335 as the new copper−molybdenum collector in the optimized reagent system can effectively enhance the selective collection effect on chalcopyrite and molybdenite, significantly improving the recovery rates of copper and molybdenum resources. Based on the optimized reagent system, a closed−circuit test was carried out, obtaining copper concentrate grade of 20.08%, molybdenum concentrate grade of 0.66%, copper recovery rate of 83.96% and molybdenum recovery rate of 62.55% respectively. Compared with the original reagent system, the copper recovery rate increased by 0.86 percentage points and the molybdenum recovery rate increased by 2.62 percentage points.This research achievement can provide a reference for the efficient recovery of similar porphyry copper−molybdenum ore resources.