NOVELTY - A photo-anode preparing method involves preparing zinc oxide-tin oxide precursor by adding ammonium bicarbonate to zinc nitrate hexahydrate and tin chloride pentahydrate, grinding mixture, putting white paste in baking box, and filtering and drying precursor to obtain composite precursor. The precursor is ground to obtain nanopowder. The nanopowder, ethyl cellulose, terpineol, acetic acid and anhydrous hexanol are prepared into slurry. The obtained slurry is coated on thin photoanode film and dried followed by burning the film and cooling the film.    USE - Method for preparing photo-anode that is utilized in dye-sensitized solar cell.    ADVANTAGE - The method enables preparing photo-anode with wide market prospect, increasing photoelectric conversion efficiency of a dye-sensitized solar cell, and improving stability of zinc oxide in acidic dyes, and tin oxide electron injection efficiency problems.    DETAILED DESCRIPTION - A photoanode preparing method involves preparing zinc oxide-tin oxide precursor by weighing zinc nitrate hexahydrate and tin chloride pentahydrate in molar ratio of 1-3:1-3 at room temperature, and grinding the zinc nitrate hexahydrate and tin chloride pentahydrate with mortar, weighing ammonium bicarbonate, adding ammonium bicarbonate to the zinc nitrate hexahydrate and tin chloride pentahydrate slowly, where molar ratio of the zinc nitrate hexahydrate, tin chloride pentahydrate and ammonium bicarbonate is 1-3:1-3:6-14, grinding the mixture to obtain fine white paste, putting the white paste in a baking box at 50-80 degrees C for 5-12 hours, washing the precursor with deionized water and anhydrous hexanol, filtering the precursor, and drying the precursor at 90-100 degrees C for 4-8 hours to obtain composite precursor. The composite precursor is processed, and temperature is controlled at 400-600 degrees C. Temperature is maintained for 1-2 hours and the composite precursor is cooled and ground to obtain nanopowder. 0.8-1.2 g nanopowder, 0.3-0.36 g ethyl cellulose, 3.2-3.8 ml terpineol, 0.1-0.2 ml acetic acid and 30-50 ml anhydrous hexanol are weighed and prepared into slurry. The obtained slurry is coated on thin photoanode film and dried at 60-80 degrees C followed by burning the film at 325-500 degrees C and cooling the film to obtain the finished product.