Abstract: In order to enhance the photocatalytic indoor air purifying efficiency, the photocatalytic technology was combined with non-thermal plasma to improve the removal of indoor air contaminants.The experimental results show that the removal rate of formaldehyde is improved sharply by plasma and photocatalysis.The removal rate of formaldehyde is increased with the increasing of excited voltage for plasma and the removal of contaminants has the maximal value under the optimal excited voltage in this paper.So the combination of photocatalysis with plasma is an applying direction of photocatalytic technology for air purification.