As one of the common manganese oxide minerals in the supergene environment, birnessite affects the migration, transformation and environmental fate of sulfur in soil. In this study, the oxidation process of sodium sulfide by birnessite was investigated. The kinds and concentrations of oxidation products of sulfides in solution were determined by spectrophotometry and ion chromatography, and the crystal structures and micro-morphologies of solid oxidation products of sulfides were analyzed by XRD and SEM. The influence of temperature, pH value of solution and the amount of added birnessite on the oxidation rate of S^2- was studied. It is observed that the main oxidation product of sulfides is elementary substance S, and the S^2- oxidation rate follows a pseudo-first-order reaction. Oxidation rate increases with elevating reaction temperature, decreasing pH value of solution and the increase of the amount of added minerals. During the redox process, birnessite is reduced to Mn(OH)₂, which can be oxidized into Mn₃O₄ by O₂ in air, and Mn₃O₄ is further transformed into MnOOH.