Formaldehyde (HCHO) is considered as a major indoor air pollutant, and may cause serious health problems for humans. Therefore, HCHO needs to be removed from indoor air. Several techniques have been developed for indoor HCHO removal, among which room-temperature HCHO oxidation is the most promising method. To obtain excellent catalytic performance, various well-designed hierarchical catalysts have been fabricated in recent years. In this review, we first summarize the strategies for gaseous HCHO removal with special regard to thermal catalytic oxidation. Then, the major influencing factors affecting the catalytic activities of supported noble metal catalysts are raised and discussed. Finally, we emphasize on hierarchical porous catalysts for room-temperature HCHO oxidation and propose the feasible mechanisms for supported noble metal catalysts. A comprehensive impression of catalysts for HCHO removal may bring a new understanding and opportunity for the design and fabrication of highly efficient and practical hierarchical catalysts for indoor HCHO oxidation. Copyright © 2021 Royal Society of Chemistry.