Abstract: The investigation on the reagent removal effects of sodium sulfide to copper and lead mixing concentrate by the sensitivity of the new combined inhibitor DW after reagent removal of mixing concentrate were carried out.It was affirmed that it had a remarkable removal effect, and there are some differences in inhabitation of the copper and lead mixing concentrate by DW.With the application of UV spectrophotometry, and solution chemistry method, the reagent removal mechanism of sodium sulfide was studied.The results showed that in the experimental conditions, a competitive adsorption happened between HS-by hydrolysis of sodium sulfide and butyl xanthate ion adsorbed on the surface of the minerals and made the butyl xanthate ion realize desorption.This is the basic reason for that sodium sulfide has a remarkable reagent removal effect on the mixed copper and lead concentrates by xanthate flotation.