Abstract: In a self-designed airtight glass box, this research compares the effect on purifying formaldehyde of six kinds of indoor ornamental plants including Chlorophytum comosum (Thunb.) Baker, Hedera nepalensis K, Koch var. sinensis (Tobl.) Rehd., Peperomia tetraphylla (Forst. F.) Hooker et Arnott, Scindapsus aureus (Linden et Andre) Bunting, Monstera deliciosa Liebm, Chamaedorea elegans Mart by fumigation method for 24 hours. The concentration of formaldehyde is 0.39 mg/m3 and 0.47 mg/m3. The results show that the six kinds of plants all have different levels of decontamination. When the concentration of formaldehyde is 0.47 mg/m3, the plants can remove 33% formaldehyde while the removal rate of the plants above ground is 14.7%. The removal rate order of the six plants is M. deliciosa Liebm, C. elegans Mart., C. comosum (Thunb.) Baker, S. aureus (Linden et Andre) Bunting, P. tetraphylla (Forst. F.) Hooker et Arnott, H. nepalensis K,Koch var. sinensisi (Tobl.) Rehd., while the removal rate order of the six plants above ground is M. deliciosa Liebm., P. tetraphylla (Forst. F.) Hooker et Arnott, H. nepalensis K,Koch var. sinensisi (Tobl.) Rehd., C. elegans Mart, S. saureus (Linden et Andre) Bunting and C. comosum (Thunb.) Baker. Soil microorganisms of S. aureus and C. elegans Mart., and purifying soil of C. comosum (Thunb.) Baker have the strongest ability to remove formaldehyde.