The　effects　of　chemical　oxygen　demand　(COD),　ammonia　nitrogen,　total　nitrogen　removal　rates　and　nitrite　accumulation　are　investigated　under　alternating　oxic-anoxic　model　in　biological　nitrogen　removal　system——sequencing　batch　reactor(SBR).　The　system　operational　effect　was　studied　by　analyzing　pollutants　removal　and　nitrite　accumulation　changes.　The　results　showed　that　the　ammonium　nitrogen　removal　rate　increased　gradually　and　reached　60%　at　last.　The　average　removal　rate　of　ammonia　nitrogen　was　50.2%.　The　average　total　nitrogen　removal　rate　was　31.0%　due　to　the　low　ammonia　nitrogen　removal　and　the　low　carbon　in　the　inflow.　The　average　COD　removal　rate　was　41.7%,　finally　the　COD　removal　rate　reached　near　60%.　The　average　nitrite　accumulation　rate　was　68.71%.　The　alternating　oxic-anoxic　model　reached　stable　nitrite　accumulation.　©　(2014)　Trans　Tech　Publications,　Switzerland.