The　anammox　granular　sludge　was　enriched　by　shortening　the　hydraulic　retention　time　(HRT)　(from　27　h　to　6.67　h)　in　the　UASB　reactor,　which　was　fed　with　ammonium　chloride　and　nitrite　as　the　substrates,　and　the　effect　of　different　HRTs　on　the　nitrogen　removal　performance　of　anammox　granule　sludge　was　studied.　After　159　d　of　operation,　the　total　nitrogen　loading　rate　(NLRTN)　reached　1.72　Kg/(m3·d),　the　total　nitrogen　removal　rate　(NRRTN)　reached　1.33　Kg/(m3·d),　and　the　removal　efficiencies　of　NH+4-N　(NRENH+　4-N)　and　NO2-　-N　(NRENO-2-N)　were　over　95%.　The　ratio　of　DNO2-　-N/DNH+4-N　was　1.31　and　DNO-3-N/DNH+4-N　was　0.24,　which　complied　with　the　chemical　reaction　stoichiometry　of　anammox.　The　colour　of　anammox　granular　sludge　changed　from　light　red　to　deep　red;　the　percentage　of　granular　sludge　larger　than　1.5　mm　was　the　highest,　which　proportionately　accounted　for　62.32%;　and　the　surface　of　the　granular　sludge　was　found,　via　Fourier　transform　infrared　spectroscopy　(FTIR),　to　contain　abundant　functional　groups.　The　inhibitory　effect　of　substrates　(NH+4-N　and　NO2-　-N)　on　anammox　was　studied　via　an　inhibition　kinetics　batch　test　using　anammox　granular　sludge　(Day　159)　in　the　UASB　reactor,　and　the　test　results　were　fitted　in　the　Haldane　inhibition　model　with　correlation　coefficients　(R2)　of　0.9912　and　0.9949.　©　2020　Technoscience　Publications.　All　rights　reserved.