Abstract: With the exploration of a copper-zinc sulfide ore extending to the depth，the geological conditions changed a lot，and a great deal of pyrrhotite appears among the ore with a more complex paragenetic relationship with minerals.The plant primarily adopted the original copper and zinc flotation process.The interference of pyrrhotite in copper concentration，and less grinding fineness resulted in worse separation index of copper and zinc，and the unreasonable flow-sheet in zinc separation resulted in lower zinc recovery.In view of these issues，the investigation on beneficiation process is carried out.Before copper concentration，pyrrhotite is removed from the ore by one-stage magnetic separation，and then the ore are re-grounded into -0.074 mm 80% from -0.074 mm 70%.At zinc concentration，the process of one scavenging，one cleaning and one clean scavenging is added to obtain the copper concentrate with Cu grade of 21.68%，Zn content of 0.62% and Cu recovery of 93.14%，and zinc concentrate with Zn grade of 48.87%，and Zn recovery of 74.92%.Compared with the closed-circuit tests index of the simulated field process，Cu grade and Cu recovery were increased by 0.70 percentage points and 1.45 percentage points and zinc content in copper concentrate decreased by 2.83 percentage points by adopting the optimized process.The zinc recovery in zinc concentrate was improved by 3.67 percentage points.Therefore，the optimized process has a good performance.

Key words: Copper and zinc sulfide ore, Pyrrhotite, Magnetic separation, Grinding fineness, Separation of copper and zinc, Zinc recovery rate