UV/persulfate　(UV/PS)　is　considered　an　effective　process　for　the　degradation　of　emerging　micropollutants　in　aquatic　media.　However,　under　the　influence　of　complex　water　matrices　such　as　wastewaters,　radicals　created　during　UV/PS　will　be　reduced　and　transformed,　so　the　chemical　process　of　effectively　obtaining　the　radicals　in　the　system　is　very　important　to　improving　degradation　efficiency.　Thus,　in　the　study,　neotame　(NEO,　an　artificial　sweetener),　as　an　emerging　contaminant,　was　selected　as　the　target　compound　to　investigate　in　terms　of　its　degradation　and　the　role　of　free　radicals　in　a　range　of　water　matrices　during　the　UV/PS　process.　Based　on　the　low　concentration　probe　method　(probe　concentration　＜=　0.2　mu　m,　more　than　3-fold　improvement　in　radical　detection　accuracy),　kinetic　modeling　was　developed　to　determine　the　role　of　primary　(center　dot　OH　and　SO4　center　dot-)　and　secondary　(　e.g.　Cl　center　dot,　Cl2-　center　dot,　CO3　center　dot-,　and　NO3　center　dot)　radicals.　Results　indicated　that　UV/PS　was　effective　in　decomposing　NEO　(＞93.7　%)　within　7　min　and　was　mainly　attributed　to　center　dot　OH　and　SO4　center　dot-.Acidic　environments　promote　NEO　degradation　with　a　greater　contribution　from　SO4　center　dot-.Natural　organic　matter　inhibited　NEO　degradation　by　quenching　radicals　(especially　center　dot　OH).　The　k　obs　of　NEO　degradation　in　the　presence　of　Cl-remained　almost　unchanged　due　to　the　production　of　Cl　center　dot　and　Cl-2-center　dot　compensating　the　depletion　of　SO4　center　dot-.　The　presence　of　HCO3-　quenched　a　part　of　primary　radicals,　which　led　to　a　decrease　in　k　obs　of　NEO　degradation,　but　CO3　center　dot-　began　to　play　a　partial　degradation　role.　In　the　presence　of　NO3-　,　UV-activated　production　of　center　dot　OH　and　NO2　center　dot　promoted　NEO　degradation.　Based　on　39　transformation　products　obtained,　3　degradation　pathways　and　7　radical　attack　ways　were　proposed　for　NEO　degradation　by　primary　and　secondary　radicals　in　the　UV/PS　system.　This　study　provides　meaningful　insight　into　the　role　of　primary　and　secondary　radicals　in　NEO　degradation　using　UV/PS　systems.