The invention discloses liquid wall paper capable of purifying the air and a preparation method thereof, and relates to the field of building coating. The liquid wall paper is prepared from the raw materials, in parts by weight: 40-50 parts of water-borne epoxy resin, 15-25 parts of acrylic resin, 3-6 parts of castor oil, 3-6 parts of linseed oil, 5-9 parts of diatomite superfine powder, 5-9 partsof expanded perlite, 4-8 parts of expanded clay, 5-9 parts of titanium dioxide, 3-6 parts of sepiolite powder, 4-8 parts of glass fiber, 1.2-2.5 parts of nanometer anion powder, 2.5-5 parts of nanometer titania, 2.5-5 parts of nanometer titanium nitride, 1.2-2.5 parts of nanometer metal powder, 2-5 parts of folium artemisiae argyi powder, 2-5 parts of tangerine peel powder, 0.8-1.5 parts of roseessential oil and 1.5-2.8 parts of menthol. The liquid wall paper has the good waterproof property and binding property, the quality is stable, the liquid wall paper is not liable to be powdered to fall down, the sources of the raw materials are rich, and the liquid wall paper can purify the air, and is green, environmentally friendly and free of toxicity.