The　performance　of　removing　the　formaldehyde　by　Alternating　Current　corona　discharge　plasma　is　studied.　The　high-frequency　Alternating　Current　power　supply,　ceramics　rings　as　the　packing　media　carrier,　two　types　of　typical　ferroelectric-barium　titanate　and　sodium　nitrite　as　the　packing　media　are　applied　in　the　experiment.　The　relations　between　removal　efficiency　of　formaldehyde　and　voltage　of　power　supply,　flow　velocity　are　mainly　investigated　and　the　effects　of　non-packing　media,　sodium　nitrite　packing　media　and　barium　titanate　packing　media　on　the　removal　efficiency　of　formaldehyde　are　also　studied　in　the　experiment.　The　power　supply　parameters　8,9,10,11　and　12　kV　and　the　gas　velocity　parameters　35　mm/s,　47　mm/s,　58　mm/s　and　70　mm/s　are　studied.　The　results　show　that　the　formaldehyde　could　be　removed　efficiently　by　high-frequency　power　supply　corona　discharge.　It　is　also　found　that　the　removal　efficiency　of　formaldehyde　can　be　enhanced　with　higher　voltage　of　power　supply　and　small　flow　velocity;　the　removal　efficiency　is　higher　with　barium　titanate　media　packed　than　with　sodium　nitrite　media　packed,　both　are　better　than　without　media　packed.　At　the　same　time,　the　mechanism　of　removal　efficiency　of　formaldehyde　is　discussed　based　on　the　experimental　results.　The　removal　of　HCHO　depends　on　two　mechanisms　(a)　collision　between　electrons　and　HCHO　molecules　and　(b)　reactions　between　gas-phase　radicals　and　HCHO　molecules.