Effects　of　triclosan　(TCS)　on　performance,　microbial　community　and　antibiotic　resistance　genes　(ARGs)　during　partial　denitrification　(PD)　were　investigated　in　a　sequencing　moving　bed　biofilm　reactor　(SMBBR).　TCS　inhibited　nitrite　accumulation;　inhibition　effect　was　more　obvious　as　TCS　concentration　increased　from　1　to　5　mg/L,　but　it　could　recover.　Extracellular　polymeric　substances　contents　increased　with　1　mg/L　TCS　addition　and　decreased　a　lot　at　5　mg/L　TCS.　Community　structure　in　biofilm　was　different　from　that　in　floccular　sludge,　but　it　was　similar　at　5　mg/L　TCS.　Illumina　sequencing　showed　that　Pseudomonas,　Aeromonas,　Shewanella　and　Thauera　became　dominant　genera.　Abundance　of　nirS　was　stable　and　higher　than　that　of　narG　and　nosZ.　High-throughput　qPCR　showed　that　mexF,　acrA-02,　fabK,　etc.　were　screened　at　5　mg/L　TCS.　IntI1　and　tnpA-04　were　abundant　mobile　genetic　elements.　The　study　furthers　understanding　of　effects　of　TCS　on　PD,　bacterial　communities　and　ARGs　in　SMBBR.