Abstract: Decomposition of formaldehyde with non-thermal plasma was studied in the paper.The relationships between formaldehyde removal efficiency and applied voltage,initial concentration,velocity of flow,supplied power were mainly investigated.The removal mechanisium of formaldehyde was studied in the plasma.The experimental results showed that the removal efficiency of formaldehyde increased with increasing applied voltage and power,and increased with decreasing initial concentration and velocity of flow under the same conditions.At the same time,absolute removal quality of formaldehyde increased with increasing applied voltage and power,initial concentration and velocity of flow.Under experimental conditions,the power of 0.092 kWh applied to remove formaldehyde per milligram.