The　application　of　anammox　technology　in　low-strength　wastewater　treatment　is　still　challenging　due　to　unstable　nitrite　(NO2--N　generation.　Partial　denitrification　(PD)　of　nitrate　(NO3--N)　reduction　ending　with　NO2--N　provides　a　promising　solution.　However,　little　is　known　about　the　feasibility　of　accelerating　nitrogen　removal　toward　the　practical　application　of　anammox　combined　with　heterotrophic　denitrification.　In　this　work,　an　ultrafast,　highly　stable,　and　impressive　nitrogen　removal　performance　was　demonstrated　in　the　PD　coupling　with　an　anammox　(PD/A)　system.　With　a　low-strength　influent　[50　mg/L　each　of　ammonia　(NH4+-N)　and　NO3--N]　at　a　low　chemical　oxygen　demand/NO3--N　ratio　of　2.2,　the　hydraulic　retention　time　could　be　shortened　from　16.0　to　1.0　h.　Remarkable　nitrogen　removal　rates　of　1.28　kg　N/(m(3)　d)　and　excellent　total　nitrogen　removal　efficiency　of　94.1%　were　achieved,　far　exceeding　the　applicable　capacity　for　mainstream　treatment.　Stimulated　enzymatic　reaction　activity　of　anammox　was　obtained　due　to　the　fast　NO2--N　jump　followed　by　a　famine　condition　with　limited　organic　carbon　utilization.　This　high-rate　PD/A　system　exhibited　efficient　renewal　of　bacteria　with　a　short　sludge　retention　time.　The　16S　rRNA　sequencing　unraveled　the　rapid　growth　of　the　genus　Thauera,　possibly　responsible　for　the　incomplete　reduction　of　NO3--N　to　NO2--N　and　a　decreasing　abundance　of　anammox　bacteria.　This　provides　new　insights　into　the　practical　application　of　the　PD/A　process　in　the　energy-efficient　treatment　of　low-strength　wastewater　with　less　land　occupancy　and　desirable　effluent　quality.