Recently,　partial　denitrification　(PDN)　-　anaerobic　ammonium　oxidation　(anammox)　process　has　been　widely　studied　in　activated　sludge　for　nitrate　wastewater　treatment.　However,　achieving　PDN-Anammox　in　biofilter　for　domestic　wastewater　treatment　was　never　reported.　In　this　study,　two　lab-scale　PDN　biofilter　and　Anammox　biofilter　were　built　up　to　treat　simulated　domestic　wastewater.　The　results　showed　that　stable　nitrogen　removal　performance　was　kept　with　averaged　effluent　nitrogen　of　10.2　mg/L.　Stable　nitrite　accumulation　performance　was　achieved　with　low　abundance　of　nitrite　reductase　gene,　while　influent　composition　influenced　nitrogen　transformation　pathway　in　PDN　biofilter.　When　treating　domestic　wastewater,　nitrification　and　partial　denitrification　led　to　the　higher　nitrite　accumulation　ratio　of　75.4%.　The　percentage　contribution　of　anammox　biofilter　was　74.6%　for　nitrogen　removal,　and　Candidatus　Brocadia　was　dominant　genus.　After　long-term　operation,　limited　substrate　concentration　caused　interspecific　competition　among　various　anammox　bacteria,　leading　to　an　increasing　proportion　of　Candidatus　Brocadia　fulgida.　PDN-Anammox　biofilter　is　a　feasible　process　to　advanced　wastewater　treatment,　which　could　save　aeration　consumption　and　carbon　source　addition,　and　reduce　sludge　production.