The invention discloses a back-spraying lamp plate, comprising PET basic material and coating layer set on the surface. Bonding layer, graphite absorbing layer and light diffused layer are coated on the basic material in turn. The bonding layer comprises propylene double self-adhesive resin, non-drying glue of water agent propylene resin and deionized water. The graphite absorbing layer comprises polyvinyl alcohol, polyvinylpyrrolidone, cationic fixing agent, defoaming agent, whitening agent, deionized water and surfactant. The light diffused layer comprises deionized water, titanium dioxide, polyacrylic acid, silicon dioxide, isopropanol, 4.5-6.0 polyvinyl alcohols and interfacial agent. The invention adopts technical project mentioned above and can make picture of lamp box cleaner, more brilliant and more lifelike. It can decrease the cost. The product can be mainly applied in back lighting advertisement signboard used in quick transportation station, department store and airport and subway so on.