S2O82-　can　be　transformed　into　Ag2+　and　SO4-　center　dot　by　catalysis　of　Ag+　.　Ag2+　and　SO4-　center　dot　are　strong　oxidant　(EAg2+0/Ag+　=　1.989　V,　E-SO4-center　dot/SO42-(0)　=　3.64　V).　The　degradation　of　methylorange　in　S2O82-　+　Ag+　system　was　studied　with　the　measurements　of　ultraviolet　spectrometry,　total　organic　carbon　(TOC),　and　high　performance　liquid　chromatography-mass　spectrometry.　When　pH　=　1,　the　dye　decolorization　efficiency　of　5　mu　mol/L　methylorange　was　up　to　100%　after　8　min　reaction　in　the　S2O82-　+Ag+　system.　Suspending　grains　were　observed　in　water　after　reaction　for　2　h,　and　the　TOC　removal　efficiency　was　up　to　8.6%.　TOC　removal　efficiency　was　10%　by　Fenton　method　under　the　same　conditions.　Considering　the　enhancement　on　organism　mineralization,　S2O82-　+　Ag+　and　Fenton　methods　show　the　similar　efficiency.