Abstract: It is difficult to suppress the sphalerite activated by cupric ion in lead -zinc -sulfur mixed concentrate due to the floatability similar with covellite. The samples in the research are lead -zinc -sulfur mixed concentrate produced by FanKou Lead and Zinc Mine in Guangdong Province. Based on the ore mineralogy study, the vertical spiral agitating mill is used to reduce the floatability of sphalerite through the improving of the degree of dissociation of mixed concentrate and scrubbing effect on the surface of sphalerite. Besides, composite inhibitor which consists of dimethyldithiocarbamate , sodium hydrogen sulfite and zinc sulfate is employed to achieve the inhibitory effect on sphalerite. With new technology and new agent, lead concentrate with 54.32 % Pb and 4.66%Zn, zinc concentrate with1.72 %Pb and 54.52 %Zn, sulfur concentrate with 2.05 %Pb and 6.05 %Zn are obtained through separation closed circuit experiment based on mixed concentrates with 12.77 % Pb and 32.91 % Zn.