The　granulation　process　of　anaerobic　ammonia　oxidation　sludge　is　slow　and　easily　affected　by　hydraulic　shear　force　and　fluctuation　in　substrate　concentration.　At　the　same　time,　the　mass　transfer　performance　of　granular　sludge　deteriorates　with　the　increase　of　particle　size,　which　leads　to　the　limitation　of　nitrogen　removal　performance　of　the　system.　In　this　paper,　a　top/bottom　variable　frequency　alternating　influent　operation　mode　was　proposed,　which　extends　the　inlet　duration　and　introduces　recirculation　to　provide　sufficient　hydraulic　shear　forces.　By　varying　the　inlet　positions　and　frequencies,　this　method　effectively　reduces　the　impact　load　of　substrate　concentration　on　Anammox　bacteria　and　enhances　the　system＇s　nitrogen　removal　performance.　The　changes　in　sludge　concentration,　particle　performance,　EPS(Extracellular　Polymeric　Substances)　secretion　and　nitrogen　removal　stability　during　operation　were　investigated.　The　results　show　that　under　this　influent　mode,　the　removal　rate　of　total　nitrogen　reached　84.80　%,　with　an　average　particle　size　of　783.67µm,　and　EPS　content　of　169.13mg/gVSS.　After　increasing　the　influent　load,　the　maximum　concentration　of　free　ammonia　was　9.70mg/L,　which　has　no　inhibitory　effect　on　the　system.　Microscopic　observations　revealed　darker　granule　colors　and　higher　heme　c　content,　indicating　better　AnAOB　activity.　The　high-throughput　sequencing　results　showed　that　the　top/bottom　variable　frequency　alternating　influent　operation　mode　can　greatly　increase　the　abundance　of　anaerobic　ammonia　oxidizing　bacteria　Candidatus_Brocadia　in　the　system,　reaching　a　peak　of　43.59%　when　the　alternating　frequency　was　3times.　The　influent　mode　accelerates　the　mixing　of　sludge　and　substrate,　shortens　the　granulation　process,　improves　sludge　activity　and　resilience　to　shock　loads,　and　realizes　the　stable　operation　of　the　anaerobic　ammonia　oxidation　system.　©　2024　Chinese　Society　for　Environmental　Sciences.　All　rights　reserved.