The　performance　of　O3-BAC　and　AC/O3-BAC　processes　was　investigated　for　treating　effluent　organic　matter　(EfOM)　from　biologically　treated　sewage　effluent　(BTSE).　It　was　found　that　DOC　removal　efficiency　was　40%　during　steady　stage　of　operation,　with　an　ozone　dose　of　2.5∼3.5mg/L　and　contacting　time　of　24min.　DOC　removal　was　mainly　happened　in　the　activated　carbon　filtration　step,　while　the　decrease　of　SUVA,　which　represents　the　aromaticity　of　organic　materials,　was　accomplished　primarily　in　the　oxidation　step.　Comparing　with　O3-BAC,　AC/O3-BAC　decreased　the　effluent　DOC　and　increased　the　aromaticity　of　effluent.　Coagulation,　sedimentation　and　sand　filtration　can　remove　a　fraction　of　large　molecular　weight　(MW)　organic　materials　and　only　slightly　decreased　the　DOC.　Oxidation　decreased　the　content　of　protein　and　tannin,　and　consequently　influenced　the　constitution　of　dissolve　organic　matter.　It　was　found　that　organic　materials　with　MW　in　the　range　of　100Da-2000Da　can　be　effectively　removed　after　O　3　or　AC/O3　oxidation.　This　fractions　as　well　as　little　MW　organic　materials　that　were　generated　during　oxidation　processes　can　be　further　removed　by　biological　activated　carbon　(BAC)　filter.　Soluble　microbial　products　were　the　main　constitute　of　BAC　effluent©　2011　IEEE.