In　order　to　improve　the　quality　and　security　of　reclaimed　water　to　reuse,　ozonization　is　used　to　oxidate　nonylphenol　ethoxylates　(NPnEO)　and　nonylphenol　(NP)　that　is　one　of　bio-degradation　products　of　NPnEO,　and　the　mechanism　of　the　oxidation　reaction　is　analyzed.　The　results　show　that　the　ozonation　processes　of　NPnEO　mainly　occur　on　the　ethoxy　chain　(EO),　which　the　EO　chain　of　NPnEO　with　various　polymerization　degrees　has　been　synchronously　degradated　into　the　smaller　polymerization　degrees.　In　the　10　minutes　of　the　reaction,　the　rate　of　a　various　polymerization　degrees　in　NPnEO　mixtures　meet　the　Poisson　distribution.　NP　is　easily　to　be　oxidized　by　ozone,　but　incomplete.　The　removal　rate　of　NP　is　90%　after　5　minutes　of　reaction.　There　are　a　lot　of　intermediary　products　to　be　produced　in　the　ozonization　process,　which　can　be　deduced　to　nonyl　alcohol　isomers　based　on　the　analysis　of　the　mass　spectrum　of　the　byproducts.