Relevance　of　clade-level　population　dynamics　of　＂Candidatus　Accumulibacter＂　to　performance　of　denitrifying　phosphorus　(P)　removal　from　municipal　wastewater　was　investigated.　Stable　denitrifying　P　removal　in　anoxic　zone　of　continuous-flow　reactor　was　achieved,　accounting　for　90%　of　total　P　removal.　Clades　IIC　and　IIF　affiliated　with　Accumulibacter　lineage　were　the　dominant　clades　during　denitrifying　P　removal,　reaching　90%　of　ppk1　clone　library.　NarG　gene　library　indicated　Gamma　and　Beta-proteobacteria　played　an　important　role　in　nitrate　reduction.　Diversity　and　abundance　of　nirS　library　was　much　more　than　nirK,　and　thus　became　the　main　functional　gene　to　execute　nitrite　reduction.　Based　on　abundance　of　nirS,　nirK　and　ppk1,　the　ratio　of　Accumulibacter　capable　of　denitrifying　P　removal　to　total　Accumulibacter　was　22%.　No　matter　whether　Accumulibacter　had　narG　gene　or　not,　high　abundance　of　narG　at　a　level　of　109　cells/(g　dried-sludge)　promoted　nitrate　reduced　to　nitrite,　ensuring　performance　of　denitrifying　P　removal.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.