Abstract: Since a silver polymetallic ore contains variety of mineral types and has complicated association relations,the experimental study on mixed flotation is carried out,investigates the effect of grinding fineness,pH,modifier,refining times on flotation index.The results show that then the grinding fineness is 75 % -0.074 mm,the reagent regime and flowsheet are optimum,the closedcircuit mixed flotation can obtain the mixed concentrate with silver grade 1 039.80 g/t,silver recovery rate 91.83 %,the silver grade of the tailings decreases to 7.66 g/t,and the copper,lead,zinc and molybdenum in the mixed concentrate are all well enriched.The recovery index is good.