The　removal　efficiency　of　effluent　organic　matter　(EfOM)　by　ozonation　was　investigated.　Ultrafiltration　separation　and　fluorescence　excitation-emission　matrix　spectroscopy　were　used　to　study　the　effect　of　ozone　dosage　on　the　variation　in　EfOM＇s　molecular　weight　distribution,　hydrophobicity-hydrophilicity,　and　fluorescence　characteristics.　The　results　revealed　that　ozonation　had　a　limited　effect　on　the　removal　of　EfOM,　but　it　could　effectively　oxidize　organic　compounds　with　strong　UV　absorption.　Ozonation　could　also　decompose　high　molecule　organic　matter　and　improve　the　biodegradability　of　EfOM.　During　ozonation,　the　organic　matter　with　MW＞100　kDa　was　completely　decomposed,　the　content　of　organic　matter　with　10　kDa＜MW＜100　kDa　and　1　kDa＜MW＜10　kDa　also　declined,　and　the　content　of　organic　matter　with　MW＜1　kDa　increased　steadily　as　the　oxidation　time　rose.　After　ozonation,　the　hydrophilic　components　in　EfOM　increased,　while　the　hydrophobic　components　and　the　acidic　components　decreased.　The　fluorescent　intensities　of　protein-like　and　humic-like　substances　in　EfOM　declined　rapidly　as　the　ozone　dosage　increased.　©　2016,　Science　Press.　All　right　reserved.