In　order　to　optimize　the　performance　of　partial　nitrification　and　denitrification　on　nitrogen　removal　in　simulated　municipal　wastewater　treatment,　partial　nitrification　and　denitrification　fillers　were　prepared　by　the　immobilization　technology,　and　a　continuous　flow　nitrogen　removal　process　was　realized.　The　results　showed　that　the　ammonia　oxidation　rate　(AOR)　of　the　partial　nitrification　immobilized　fillers　after　activity　recovery　could　reach　39.06　mg∙(L∙h)−1,　and　the　nitrite　accumulation　rate　(NAR)　maintained　at　about　96.60%.　The　response　surface　methodology　(RSM)　was　used　to　investigate　the　effects　of　DO,　HRT　and　filling　rate　in　the　partial　nitrification　process　of　immobilized　fillers　on　the　ammonia　nitrogen　removal　rate　(ARR)　and　NAR,　and　a　quadratic　regression　model　was　established　to　predict　the　best　operating　conditions:　HRT　of　3.48　h,　DO　of　3.64　mg∙L−1,　the　filling　rate　of　20%.　Under　these　conditions,　the　post-denitrification　immobilized　fillers　were　installed,　the　average　mass　concentration　of　total　nitrogen　(TN)　in　the　effluent　was　2.29　mg∙L−1　with　a　stable　removal　rate　of　94.27%　when　the　average　C/N　was　2.82.　This　indicates　that　the　process　had　a　good　nitrogen　removal　performance　from　municipal　wastewater.　The　results　of　high-throughput　sequencing　showed　that　the　functional　bacteria　in　the　partial　nitrification　and　denitrification　immobilized　fillers　largely　proliferated　and　always　maintained　dominance.　©　2022　Science　Press.　All　rights　reserved.