The　effect　of　fibrillation　earthworm　feeding　on　degradation　of　dissolved　substances　has　been　studied　by　the　intermittent　test.　As　the　earthworm　density　changes,　the　conversion　of　certain　substances　in　the　activated　sludge　system,　including　the　sludge　activity,　ammonia　nitrogen　and　COD　treatment　effect　has　been　investigated.　From　the　perspective　of　predation,　it　may　reduce　the　removal　efficiency　of　system　for　NH4+-N　when　insect　fibrillation　earthworm　body　present　in　the　reactor　because　of　the　feeding　effect　on　nitrifying　bacteria.　The　results　show　that　there　is　some　impact　on　the　degradation　rate　of　ammonia　degradation　for　the　presence　of　fibrillation　earthworm,　but　little　for　the　removal　effect　of　final　ammonia　and　COD,　especially　the　final　ammonia.　And　by　measuring　the　value　of　OUR,　the　right　flutter　earthworm　density　will　play　an　active　role　in　bacteria　in　the　activated　sludge　system.　©　2012　IEEE.