Decomposition　of　formaldehyde　with　high-frequency　discharge　plasma　was　studied　in　the　paper.　The　relationships　between　formaldehyde　removal　efficiency　and　applied　voltage,　discharge　current,　power　supply　frequency　were　mainly　investigated.　The　effect　of　non-filling,　sodium　nitrite　filling　and　barium　titanate　filling　were　also　compared.　The　experimental　results　showed　that　the　removal　efficiency　of　formaldehyde　increased　with　increasing　applied　voltage,　discharge　current　and　power　supply　frequency.　Under　the　same　conditions,　the　reactor　with　filling　had　higher　removal　efficiency　than　the　reactor　without　filling.　Furthermore,　the　reactor　with　barium　titanate　filling　had　higher　removal　efficiency　than　the　reactor　with　sodium　nitrite　filling.