The　implementation　of　anammox　based　process　remains　a　challenge　in　treating　low　ammonium　wastewater.　In　present　research,　partial　nitrification/anammox　(PN/A)　performance　was　investigated　in　the　integrated　fixed-film　activated　sludge　(IFAS)　system.　The　influent　of　the　IFAS　reactor　was　simulated　residential　domestic　sewage.　The　nitrite　oxidizing　bacteria　(NOB)＇s　proliferation　was　observed　when　dissolved　oxygen　(DO)　concentrations　were　0.65　and　0.35　mg/L.　By　conducting　intermittent　aeration　(aerobic　1　min/anoxic　5　min)　and　low　DO　condition　(0.20　mg/L)　strategy,　the　IFAS　reactor　performed　good　nitrogen　removal　performance.　The　average　total　nitrogen　(TN)　removing　efficiency　and　TN　removing　rate　reached　80.6%　and　0.13　kg　N/(m(3).d),　respectively.　In　long　term　operation,　extracellular　polymeric　substance　(EPS)　concentration　of　activated　sludge　was　largely　increased,　which　favored　the　formation　of　granules.　The　maximum　frequency　diameter　of　sludge　flocs　was　increased　to　1000　mu　m.　The　anammox　bacteria　and　ammonium　oxidizing　bacteria　(AOB)　were　both　enriched　within　activated　sludge　and　biofilm.　High　throughput　analyzing　result　implied　that　anammox　bacteria　and　AOB＇s　abundances　were　2.01%　and　5.04%　in　activated　sludge,　while　2.43%　and　2.45%　in　biofilm,　respectively.