Abstract: In order to improve the flotation separation index of lead and zinc in a lead-zinc sulfide ore in Guangdong，in view of the difficulty of flotation separation of lead and zinc，the test of lead and zinc in turn preferential flotation process is carried out.Under the condition of reducing the pH value of the pulp （the pH value is reduced from field 12 to about 10），the combined inhibitor zinc sulfate + sodium alginate is used. On the basis of the raw orelead grade of 4.58% and the zinc grade of 9.33%，the lead concentrate with lead grade of 55.12% and lead recovery of 86.05% and the zinc concentrate with zinc grade of 52.68% and zinc recovery of 95.37% are finally obtained. The test index is better.The contact angle and zeta poten‐ tial test results show that the inhibitor zinc sulfate + sodium alginate is easier to adsorb on the surface of sphalerite and change its hydrophobicity. The combined inhibitor is expected to be applied in actual pro‐ duction，which can reduce the amount of lime in the test process and play an important role in protecting the environment.

Key words: galena, sphalerite, combined inhibitors, flotation separation