Ammonium　nitrogen　and　total　nitrogen　removal　influence　factors　and　treating　effect　of　A/O　nitrogen　removal　process　were　investigated　using　synthetic　wastewater　as　studied　object.　The　A/O　nitrogen　removal　process　expert　control　system　was　established　based　on　experiment　results　and　expert　knowledge.　The　practices　demonstrated　that　utilizing　nitrification　and　denitrification　expert　control　system　could　obtain　quickly　the　causes　and　solution　ways　of　the　reducing　of　ammonia　nitrogen　and　total　nitrogen　removal　rates,　reaching　the　objectives　of　meeting　standard,　stability,　high　efficiency　and　low　cost.