Recently,　highly　efficient　activation　of　peroxymonosulfate　(PMS)　by　S-doped　cobalt-based　catalysts　are　receiving　increased　attention.　The　effect　of　S　is　worth　exploring　since　it　has　a　great　influence　on　PMS　activation　performance.　In　this　work,　dimethyl　sulfoxide　was　adopted　as　an　S　source　and　loaded　on　bamboo　biochar　(BB)　with　Co　to　form　CoS/BBC,　which　served　as　an　efficient　catalyst　for　PMS　activation　to　degrade　sulfamethoxazole　(SMX).　The　experiment　results　showed　that　CoS/BBC　exhibits　an　excellent　catalytic　activity　and　the　SMX　(20　mg/L)　can　be　completely　degraded　under　the　attack　of　species　of　·OH,　SO4-·,　1O2　and　electron　transfer.　The　SMX　degradation　conformed　to　pseudo　first-order　kinetics　with　rate　constant　reaching　0.442　min-1　in　10　min　under　the　optimal　conditions　(a　catalyst　dose　of　0.02　g/L,　a　PMS　dose　of　0.3　g/L　and　an　initial　pH　=　7.0).　The　electrochemical　experiments　and　density　functional　theory　(DFT)　calculation　revealed　that　the　introduction　of　S　can　accelerate　electron　transfer　and　promote　the　decomposition　of　PMS　while　facilitating　Co(III)/Co(II)　redox　cycling.　Furthermore,　liquid　chromatograph-mass　spectrometer　(LC-MS)　and　ecological　structure　activity　relationships　(ECOSAR)　proved　that　the　degradation　process　of　SMX　in　CoS/BBC/PMS　system　has　low　ecotoxicity　and　is　harmless　to　the　environment.　This　work　provides　a　new　strategy　for　enhancing　electron　transfer　by　S-doped　metal　materials　and　the　synthesis　of　efficient　catalysts　for　SMX　removal.　©　2022　Elsevier　Ltd.