The invention belongs to the field of air purification and disinfection, and provides an air purifying device, which comprises at least two layers of glass sheets, wherein a gap is formed between any two adjacent layers of glass sheets; the side face of any layer of glass sheet is provided with a photocatalyst coating; at least one layer of glass sheet is provided with an ultraviolet ray generator; and the photocatalyst coating consists of nanoscale platinum particles and nanoscale titanium dioxide particles. In the invention, molecules of organic compounds in the air are decomposed and split into atoms through nanoscale platinum coated on glass, ultraviolet rays of which the wavelengths are 365-400 nanometers are irradiated onto the glass coating through an ultraviolet ray emitter, and the atoms are reduced into water, carbon dioxide and oxygen once again under the photocatalysis action of the titanium oxide on the coating. The air purifying device can be used for treating formaldehyde, toluene, dimethylbenzene, ammonia, radon, ether, heterocyclic organic matters, dioxin, viruses, pollen and the like in the air.