Abstract: Thickener overflow of a lead-zinc flotation tailing contain quantities of ultra-fine pyrite with particle size of 99.40% passing 40 μm and 33.50% passing 5 μm.Most of pyrite particles are finer than 30 μm，exists in form of idiomorphism or semidiomorphism granular with sound liberation degree.94.93% of pyrite are monomer and enriched in 40~5 μm grade.To increase the utilization rate of resource，improve the business performance of enterprises，decrease the tailings stockpiling and discharging，and optimize the parameters of tailing pond，flotation experiments of the ultra-fine pyrite were carried out.The results showed that sulfur concentrate with sulfur grade of 46.90% and recovery of 86.64% was obtained through the process of two roughing-two cleaning，and middles back to the flow-sheet in turn.With good flotation index，the process can be as the basis for design.

Key words: Ultrafine, Pyrite, Flotation