The purpose of this study is to improve the performance of indoor air purifiers. To this end, the performance and structure of indoor air purifiers were analysed in this paper. Simple background reduction method and the natural attenuation deduction method were used to analyse the performance test and structure of indoor air purifier. The study found that the purifier A has the best ability to remove formaldehyde, which can remove 80% of formaldehyde within half an hour; purifier B can remove 70% of formaldehyde within half an hour. Therefore, the structure of purifiers affects the purification efficiency, and in the design of the purifier structure, more attention should be paid to the reasonable ratio of radiation field, concentration field and flow field.