A　two-sludge　system　with　separated　phosphorus　removal　unit　and　nitrification　unit　was　used　to　treat　the　actual　municipal　sewage　deficient　in　organic　carbon　sources,　with　the　carbon/nitrogen　(C/N)　ratio　of　4.39.　The　system　was　first　operated　as　anaerobic/oxic-nitrification　(A/O-N)　mode　for　60　days　(phase　I),　and　then　transformed　into　anaerobic/anoxic/oxic-nitrification　(A/A/O-N)　mode　for　the　next　following　80　days　(phase　II).　Noteworthy,　oxygen　and　nitrate　acted　as　electronic　acceptors　for　phosphorus　removal　in　chronological　order.　Results　indicated　that　deep　phosphorus　removal　and　complete　nitrification　were　achieved　at　both　phase　I　and　phase　II,　and　the　system　exhibited　a　higher　microbial　diversity.　Microbial　community　abundance　on　genus　level　analysis　indicated　that　Dechloromonas　and　Accumulibacter　were　respectively　accumulated　with　11.6　and　2.42%　abundance　(A/A/O　sludge);　and　9.31　and　1.29%　Nitrospira　and　Nitrosomonas　occupied　the　biofilm,　and　they　performed　denitrifying　phosphorus　removal　(DNPR)　and　nitrification,　respectively.