In　order　to　investigate　the　influence　of　copper　ions　on　settleability　and　denitrogenation,　three　sequencing　batch　reactors　(SBR)　equipped　with　PLC　system　were　operated　by　synthetic　wastewater　using　acetate　as　the　single　carbon　source.　After　the　nitrification　and　denitrification　process,　when　the　system　was　stable,　SBR　1#　was　operated　as　a　control　test,　copper　sulphate　solution　was　dosed　to　SBR　2#　and　SBR　3#　under　anoxic　and　aerobic　conditions　in　each　cycle.　The　results　show　that　the　adding　of　Cu　2+　under　anoxic　zone　leads　to　deterioration　of　sludge　sedimentation,　but　in　the　aerobic　stage,　Cu　2+　does　not　cause　the　deterioration　of　sludge　settling.　The　presence　of　Cu　2+　under　anoxic　and　aerobic　conditions　do　not　cause　proliferation　of　filamentous　bacteria.　The　dosing　of　Cu　2+　stimulated　the　secretion　of　more　extracellular　polymers　against　the　toxic　effects　of　Cu　2+　and　inhibited　the　ability　of　microorganisms　to　store　PHA.　The　presence　of　Cu　2+　under　anoxic　condition　of　SBR　2#　is　contributed　to　the　formation　of　shortcut　nitrification　and　denitrification,　but　the　shortcut　nitrification　can　not　be　maintained　by　longterm　dosing.　The　adding　Cu　2+　in　the　aerobic　stage　of　SBR　3#　causes　the　rapid　loss　of　nitrification　and　denitrification.　©　2017,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.