NOVELTY - Preparation of honeycomb structured graphene/zinc oxide nanorod composite film involves preparing mixed solution of zinc salt and hexamethylenetetramine with concentration of 10-30 mM, stirring at room temperature for 5-10 minutes, adding resultant mixed solution to reactor, immersing honeycomb structured graphene/zinc oxide nanorod composite film in the resultant mixed solution at 80-90 degrees C for 4-6 hours, washing resultant film with deionized water, and drying.    USE - Preparation of honeycomb structured graphene/zinc oxide nanorod composite film used for photoelectric conversion device (all claimed).    ADVANTAGE - The method enables simple preparation of honeycomb structured graphene/zinc oxide nanorod composite film. The honeycomb structured graphene/zinc oxide nanorod composite film improves capture efficiency of light energy, and separation and transfer efficiency of photo electrons-holes. The photoelectric conversion device using the honeycomb structured graphene/zinc oxide nanorod composite film has excellent photoelectric conversion efficiency.    DETAILED DESCRIPTION - Preparation of honeycomb structured graphene/zinc oxide nanorod composite film involves preparing mixed solution of zinc salt and hexamethylenetetramine with concentration of 10-30 mM, stirring at room temperature for 5-10 minutes, adding resultant mixed solution to reactor, immersing honeycomb structured graphene/zinc oxide nanorod composite film in the resultant mixed solution at 80-90 degrees C for 4-6 hours, washing resultant film with deionized water, and drying. The honeycomb structured graphene/zinc oxide nanorod composite film is prepared immersing honeycomb structured graphene film in 10-30 mL zinc acetate ethanol solution with concentration of 10-30 mM for 20-50 seconds, blowing nitrogen, placing resultant product in muffle furnace, heating in nitrogen atmosphere at 200-300 degrees C for 20-30 minutes, and immersing obtained product in nanocrystalline seed solution prepared by adding 10-100 mg zinc acetate to 10-100 mL anhydrous methanol, heating at 40-80 degrees C, adding 10-20 mL sodium hydroxide methanol solution with concentration of 0.01-0.03 M, heating at 40-80 degrees C for 1-5 hours, and cooling. The honeycomb structured graphene film is prepared by dissolving 10-100 mg graphene oxide/surfactant composite to 10-100 mL organic solvent, evaporating organic solvent in relative humidity of 60-95%, forming graphene oxide thin film, placing the film in a reactor, adding 2-100 mu L reductant, and heating at 90-120 degrees C for 1-30 hours. The graphene oxide/surfactant composite is prepared by adding 0.5-2 g graphite powder having particle diameter of 2-45 mu m, 0.9-3.5 g potassium persulfate and 0.9-3.5 g phosphorus pentoxide to 4-160 mL concentrated sulfuric acid with concentration of 98%, stirring, heating at 70-90 degrees C for 5-10 hours, cooling to room temperature, filtering by cellulose acetate membrane with pore size of 0.2-0.5 mu m, washing with deionized water, drying, obtaining preoxidized graphite, dispersing obtained product in 15-60 mL concentrated sulfuric acid with concentration of 98%, stirring, adding 2-10 g potassium permanganate, stirring at 30-50 degrees C for 2-5 hours, diluting with 50-200 mL deionized water, adding 1-4 mL 30% hydrogen peroxide aqueous solution, filtering, washing with 37.5% hydrochloric acid and water in a volume ratio of 1:5-1:10, and then with deionized water to remove excess metal ion and acid, separating, obtaining aqueous solution of graphene oxide, adjusting pH to 8-11 using 1-3 M alkali, adding 0.1-2 mg/mL solution of organic surfactant, removing organic solvent by rotary evaporation, and drying in vacuum at 25-100 degrees C.