Abstract: In order to realize the efficient development and utilization of a low-grade lead-zinc ore in Yunnan，based on the study of ore process mineralogy，the beneficiation process tests of low pH medium and high pH medium are carried out by using lead and zinc sequential preferential flotation process.The test results show that the process stability of low pH medium is insufficient，and the applicable range of collector and foaming agent is narrow. Lead concentrate with lead grade of 75.34% and lead recovery of 96.46%，zinc concentrate with zinc grade of 54.69% and zinc recovery of 88.12% are obtained by high pH medium process closed-circuit test. Lead concentrate contains silver 343.64 g/t，silver recovery is 74.24%， zinc concentrate contains silver 59.72 g/t，silver recovery is 12.46%，and the total recovery of silver in lead and zinc concentrate is 86.70%.Good test indexes are obtained.

Key words: lead-zinc sulfide ore, flotation, lead-zinc separation, pH value medium