NOVELTY - Preparation of multilevel pore composite metal oxide includes dissolving chemical template in water, adding metal salt, continuously stirring at room temperature, ball milling halogen-treated and clean egg shell, respectively adding hydrochloric acid, sulfuric acid, nitric acid, and potassium hydroxide, soaking, drying to remove water, adding the metal salt solution with citric acid, adding halogen-treated and clean egg shell, continuously stirring at room temperature until forming sol, adjusting pH with ammonia water, raising the temperature, stirring to form a wet gel, and drying the gel.    USE - Preparation of multilevel pore composite metal oxide (claimed) used for catalysis, fuel cell, and electrode material fields.    ADVANTAGE - The method has low cost and good repeatability, is simple and easy to control, and provides multilevel pore composite metal oxide with uniformly distributed apertures, where pore walls are communicated with each other.    DETAILED DESCRIPTION - Preparation of multilevel pore composite metal oxide comprises dissolving chemical template in water, stirring at 400-800 revolutions/minute (rpm) at 40-60 degrees C for 0.5-1 hour, where chemical template is surfactant i.e. quat. ammonium salt surfactant or block copolymer i.e. polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, where the concentration of surfactant or block copolymer is 0.001-0.03 mol/L, adding 0.041-0.35 g metal salt per ml of solution, continuously stirring at room temperature for 1-2 hours, where metal salt is lithium (Li), nickel (Ni), copper (Cu), and zinc (Zn) nitrate and acetate mixture, metal ion concentration of metal salt is 0.15-2 mol/L, and mass ratio of Li, Ni, Cu, and Zn metal salts is 0.1-6:1-7:1-8:2-14, ball milling halogen-treated and clean egg shell for 6 hours, respectively adding 6-12 mol/L hydrochloric acid, 8-18 mol/L sulfuric acid, 6-14 mol/L nitric acid, and 2-6 mol/L potassium hydroxide, soaking for 2-6 hours, drying to remove water, adding the metal salt solution with citric acid, where mol ratio of metal ion and citric acid is 1-2, adding halogen-treated and clean egg shell, where each ml metal salt solution is added with 0.005-0.05 g halogen-treated and clean egg shell, continuously stirring at room temperature until forming sol, adjusting pH at 6-8 with ammonia water, raising the temperature to 80-100 degrees C, stirring to form a wet gel, putting the gel in drying box at 80-100 degrees C for 6-24 hours to form dry gel, putting the dry gel in muffle furnace, raising the temperature to 500-800 degrees C at 1-10 degrees C/minute, and heat preserving for 4-6 hours.