The　degradation　rates　of　amitriptyline　(AMT)　by　UV,　UV/H2O2,　UV/Fenton　were　investigated　in　ultrapure　water　in　this　study.　The　results　showed　that　addition　of　H2O2　significantly　enhanced　the　UV　degradation　of　AMT.　Approximately　100%　degradation　was　achieved　in　120　min　after　addition　of　0.5　mM　H2O2　in　solution,　while　only　46.9%　degradation　was　obtained　without　H2O2　addition.　AMT　degradation　was　enhanced　with　the　increase　of　H2O2　concentrations　and　the　decrease　of　initial　AMT　concentrations.　It　was　also　found　that　the　alkaline　pH　is　more　favorable　than　the　acidic　and　neutral　condition　for　AMT　degradation.　Moreover,　the　effect　of　Fenton＇s　reagent　((Fe2+/H2O2)　on　the　degradation　of　AMT　was　investigated,　and　the　results　demonstrated　that　the　UV/Fenton　system　was　more　effective　than　the　UV/H2O2　process　for　AMT　degradation.　Under　UV,　UV/H2O2　and　UV/Fenton　processes,　the　degradation　of　AMT　followed　pseudo-first-order　kinetics　in　aqueous　solution.　Finally,　the　primary　degradation　intermediates　and　end　products　of　AMT　were　detected　by　LC/MS/MS　and　possible　pathways　under　UV　irradiation　were　analyzed.