The accumulation of electrolytic manganese residue (EMR) has become a serious problem and its recycling will be of great benefit to protect the environment and assist sustainable development. The reusing method was conducted by leaching EMR with sulfuric acid and the optimal leaching condition was 1:3 (g/g) as the ratio of solid to liquid with 20% (g/g) H2SO4 , heating at 90 ℃ for 3 hours, which aims at extracting Mn in a sulfuric acid medium. The produced MnSO4 solution was precipitated by adding alkali and oxidized in aqueous phase. The oxidized products were characterized by various techniques, including X-ray powder diffraction (XRD), Fourier transform infrared (IR) spectrometry, vibrating sample magnetometry (VSM), with Brunauer-Emmett-Teller (BET) specific surface area instrument and laser particle size analyzer. The final products were confirmed to be a single-phase Mn3O4 . The accumulation of electrolytic manganese residue (EMR) has become a serious problem and its recycling will be of great benefit to protect the environment and assist sustainable development. The reusing method was conducted by leaching EMR with sulfuric acid and the optimal leaching condition was 1: The resulting MnSO4 solution was precipitated by adding 3 (g / g) as the ratio of solid to liquid with 20% (g / g) H2SO4, which at temperatures of 90 ° C for 3 hours, which aims at extracting Mn in a sulfuric acid medium. The oxidized products were characterized by various techniques including X-ray powder diffraction (XRD), Fourier transform infrared (IR) spectrometry, vibrating sample magnetometry (VSM), with Brunauer-Emmett- Teller specific surface area instrument and laser particle size analyzer. The final products were confirmed to be a single-phase Mn3O4.