Radiolysis　of　sulfamethazine　(SMT)　was　characterized　under　different　conditions　in　this　research.　SMT　solutions　(20　mg·L-1)　were　irradiated　in　the　presence　of　0,　1,　2,　4,　10　and　20　mmol·L-1　S2O82-,　respectively.　The　results　show　that　gamma　radiation　was　effective　in　both　SMT　degradation　and　TOC　removal,　and　the　synergistic　effects　of　gamma　radiation　with　persulfate　(S2O82-)　were　obviously.　The　degradation　reactions　conformed　to　the　pseudo-first-order　reaction　kinetics.　With　absorbed　doses　of　1　kGy　to　5　kGy,　TOC　removal　rates　were　dramatically　elevated　after　S2O82-　was　added　-3.5%　to　22.8%　and　14.1%　to　70.1%,　respectively.　In　the　process,　three　ions　(SO42-,　HCOO-　and　CH3COO-)　were　detected　to　be　released　from　the　radiolytic　solutions　by　ion　chromatography　(IC).　Furthermore,　complicated　products　were　identified　by　GC-MS.　The　normal　N-containing　ions　(NO2-,　NO3-　and　NH4+)　were　not　detected　in　the　process.　The　pathways　and　mechanisms　for　the　radiolytic　process　in　the　aqueous　solution　were　proposed.　©　2017,　Science　Press.　All　right　reserved.