Abstract: Because of inadequate liberation degree of monomer copper mineral，poor inhibition effect of pyrite，and undissociated copper-sulfur mineral combination cycle repeatedly in the form of middlings，result in instability process of floatation process and production index is not ideal.In order to improve the production index，on the basis of on-site process investigation to find the reasons that affecting production index，copper separation optimization on laboralory scale research was conducted.The results show that by using one roughing-three cleaning-three scavenging，one concentrate tailings and one scavenging concentrate are mixed and returned to regrinding after combining and other middlings are returned in order，grinding fineness increased from -0.043 mm account 75% to 94%，bleaching powder and sodium humate replace lime as inhibitor for pyrite in copper concentrating，Z-200 replaces butyl-xanthate as copper collector.Copper concentrate with Cu grade of 16.62% and Cu recovery of 80.75% was obtained，Cu grade and Cu recovery is increased by 2.05 and 0.54 percentage points respectively in comparison with the production field index.The new process is changed a little from the original on-site process，but the production index is improved significantly，so it is applicable to optimize for the original process.

Key words: High-sulfur refractory copper ore, Beneficiation process optimization, Middlings regrinding, Beneficiation index