We　investigated　the　nitrogen　removal　performance　of　anaerobic　ammonium-oxidizing　(anammox)　granules　in　a　reactor　under　continuous　cultivation　at　low　acetate　concentration.　As　a　comparison,　we　applied　batch　tests　to　measure　the　nitrogen　transformation　and　removal　pathways　of　granules　obtained　from　the　coupling　reactor.　The　reactor　exhibited　excellent　anammox　and　denitrifying　performances　at　low　acetate　concentration.　During　steady　phase,　removal　rates　of　NH4+-N,　NO2--N,　and　TN　were　93.84%,　94.62%,　and　86.46%,　respectively.　Batch　tests　indicated　that　the　coupling　anammox　granules　exhibited　good　anammox,　nitrification,　and　denitrification　activities.　The　total　nitrogen　removal　rate　of　coupling　granules　was　12.46　mg·(g　MLSS·h)-1.　Nitrifying　bacteria　in　the　system　were　capable　of　consuming　the　dissolved　oxygen,　thus　lessening　the　inhibitory　effect　of　oxygen　on　anammox　bacteria.　As　a　result,　activity　of　ammonia-oxidizing　bacteria　(AOB)　was　higher　than　that　of　nitrite-oxidizing　bacteria　(NOB).　Denitrification　rates　for　nitrite　and　nitrate　were　1.89　and　3.59　mg·(g　MLSS·h)-1,　respectively.　When　nitrite　and　nitrate　were　present　simultaneously,　denitrifying　bacteria　reduced　nitrate　to　nitrite　first.　©　2016,　Science　Press.　All　right　reserved.