NOVELTY - A zinc-doped coating is prepared by reacting tetraethyl orthosilicate, ethyl alcohol, and ammonia water, adding polyethylene glycol, refluxing in ammonia suspension colloid catalyst to obtain silicon dioxide suspension colloid coating, carrying out pulling method to obtain silicon dioxide thin film, coating on glass surface, dissolving tetrabutyl titanate and zinc chloride pentahydrate in ethyl alcohol, adding water and diethanolamine, hydrolyzing, stirring to obtain zinc-doped titanium dioxide sol, carrying out pulling method to obtain zinc-doped titanium dioxide film, and coating.    USE - Preparation of zinc-doped coating for solar energy glass plate.    ADVANTAGE - The preparation improves titanium dioxide photo-catalytic efficiency and product is self-cleaning and has anti-reflection property.    DETAILED DESCRIPTION - A zinc-doped coating is prepared by mixing analytically pure tetraethyl orthosilicate (Si(OC2H5)4), absolute ethyl alcohol (C2H5OH), and ammonia water at room temperature in which volume ratio Si(OC2H5)4:water (H2O):ammonia (NH3):C2H5OH is 1:2:0.6:37, adding 1ml/L solution polyethylene glycol-400, sealing, aging, refluxing in NH3 suspension colloid catalyst to obtain silicon dioxide (SiO2) suspension colloid coating, carrying out pulling method to obtain SiO2 thin film, coating film on glass surface, dissolving analytically pure tetrabutyl titanate (Ti(OC4H9)4) and zinc chloride pentahydrate (ZnCl2.5H2O) in absolute C2H5OH, slowly adding water and diethanolamine (NH(C2H5OH)2) as inhibitor, hydrolyzing Ti(OC4H9)4, continuously stirring to obtain zinc-doped titanium dioxide (TiO2) sol in which molar ratio Ti(OC4H9)4:C2H5OH:H2O:NH(C2H5OH)2 is 1:26.5:1:1, carrying out pulling method to obtain zinc-doped TiO2 film, coating obtained film on glass surface with SiO2 film, heating to crystallize non-crystal TiO2 to anatase form, increasing temperature to convert anatase type to TiO2 rutile type in which crystal type of TiO2 is dependent on temperature and time for heating, such as TiO2 is amorphous at less than or equal to 300 degrees C, TiO2 is anatase at 400 degrees C, and TiO2 is rutile at 550 degrees C, prolonging heat-treatment, gradually growing crystal on thin film to reduce specific surface are and catalytic activity, and reducing temperature.