Abstract: With the continuous improvement of material life, formaldehyde has become the main substance of indoor air pollution. For indoor air purification, the removal of formaldehyde becomes particularly important. Manganese dioxide (MnO₂) was in-situ loaded onto non-woven fabric made of polyethylene terephthalate (PET) by water bath method, which has mild reaction conditions and simple processing. The synthesized MnO₂/PET composites were characterized by scanning electron microscope (SEM), diffraction of X-rays (XRD) and specific surface area test (BET), imitating the indoor environment to make the initial concentration of 2.84 mg/m³, after 6 h, and making the concentration of the formaldehyde to 0.33 mg/m³, with the removal rate of formaldehyde reaching 88.29%. This study provides an efficient method for the synthesis of formaldehyde oxidation catalyst, which provides a new idea for indoor formaldehyde catalysis.