The invention relates to a method for preparing a cathode material Li4Ti5O12 of a high-performance lithium ion battery. The method comprises the following steps of: adopting the combined method of sol-gel and microwave treatment to prepare micro powder of nano-class Li4Ti5O12, and simultaneously modifying Li4Ti5O12 by carbon doping and metallic doping. The method utilizes the sol-gel method to effectively control chemical composition, phase composition and powder size of the Li4Ti5O12, thereby improving the uniformity and the electric conductivity of the Li4Ti5O12; simultaneously by utilizing the characteristics of the microwave technique of quick temperature rise, even heating and conglobation resistance, the high-power industrial microwave oven is used for treatment, so that the treatment time of the Li4Ti5O12 is greatly shortened, the yield is greatly improved, and the cost and the energy consumption of the material are reduced, the process is simplified, the efficiency on the industrialized production of the lithium ion battery is improved, and the industrialized application is easily achieved; and by doping carbon and metallic elements, the electric conductivity of lithium iron phosphate is greatly improved, and the charging and discharging capacities and the cycle index of the lithium iron phosphate are simultaneously and effectively increased.