The invention discloses a spray for preventing and treating psoriasis. The spray is prepared from the following raw materials in parts by weight: 20-28 parts of collagen, 5-10 parts of propolis, 23-27parts of rhizoma atractylodis, 15-25 parts of fruit of summer cypress, 6-12 parts of Bingpeng powder, 5-10 parts of glycerol, 10-20 parts of mannitol, and 30-50 parts of water. In the spray for preventing and treating psoriasis, the main raw material collagen supplements collagen for the skin, glycerol can moisturize the skin so as to prevent the skin from becoming dry, all raw materials coordinate with each other, so that the spray has functions of diminishing inflammation, sterilizing, resisting corrosion, stopping itching, astringing, generating skin, healing, inhibiting bacteria, eliminating mould, and immunizing. Further, the spray uses simple raw materials, is low in price and low in manufacture cost, is convenient to use, contains no antibiotics, does not cause poor tolerance whenbeing used for a long time, and is safe and effective.