Ozonation　is　a　widely　used　in　sludge　reduction.　However,　it　is　not　clear　whether　ozone　can　effectively　reduce　antibiotic　resistance　genes　in　sludge.　In　this　paper,　we　used　the　propidium　monoazide　(PMA)　modified　quantitative　polymerase　chain　reaction　(qPCR)　method　to　study　the　changes　of　21　antibiotic　resistance　genes　in　activated　sludge　during　ozonation　treatment.　The　results　showed　that　ozone　oxidation　could　effectively　reduce　the　absolute　abundances　(resistance　genes＇　copies　in　1　mL　sludge)　of　21　antibiotic　resistant　genes　in　activated　sludge,　and　their　total　amount　decreased　by　75.44%　under　the　ozone　consumption　of　0.31　g·g-1(TSS).　Despite　the　decline　in　absolute　abundance,　relative　abundances　(resistance　gene＇　copies/16S　rRNA　gene＇s　copies)　of　most　resistance　genes　in　sludge　increased　during　sludge　ozonation,　indicating　that　the　proportion　of　antibiotic　resistant　bacteria　in　the　sludge　might　increased.The　absolute　abundance　of　class　I　integron,　an　important　genetic　element　for　the　horizontal　transfer　of　resistance　genes,　also　decreased　with　the　increase　of　ozone　consumption,　while　its　relative　abundance　increased.　©　2017,　Science　Press.　All　right　reserved.