Abstract: ObjectiveSulfide minerals have always been the most common target enrichment mineral in the field of non-ferrous metals flotation. The effect of the reagent system on sulfide ore flotation is usually considered to determine the flotation concentrate index, but the effect of pulp surface tension on sulfide ore flotation is usually ignored. Method In this article, the effect of pulp concentration, fineness, associated minerals, collector and frother on the surface tension of pyrite flotation pulp was investigated. At the same time, the effect of pulp surface tension on the recovery of pyrite flotation was explored by pure mineral flotation.Result The slurry concentration test shows that the surface tension first decreases and then increases with the increase of slurry concentration. When the concentration is 30%, the surface tension reaches the minimum value of 69.63 mN/m, and the surface tension of the associated mineral quartz is closest to water at natural pH value. The fineness test shows that the pulp surface tension decreases with the decrease of pyrite fineness. The test results of collector and frother show that the surface tension of pulp with MA-1+HX609 is lower than that with other combinations. Conclusion The pure mineral flotation test shows that the surface tension of pulp is inversely proportional to the pyrite recovery, and the smaller the surface tension, the higher the recovery rate of pyrite.