The invention relates to a preparation method of rare earth motorcycle engine oil. According to the method, an antifoaming agent and a dispersant are added into kerosene; after the mixture is uniformly stirred, nanometer rare earth is added in a high-speed shearing state, so that the nanometer rare earth is completely dispersed in the kerosene; after an antioxidant, base oil and microcrystal wax are added, the rare earth motorcycle engine oil is obtained. Through the product of the rare earth motorcycle engine oil, an engine approaches to zero abrasion; the service life of the engine is prolonged; an ultrastrong oil film is formed; the long-time stable oil pressure is maintained; the oil exchange mileage breaks through the oil exchange period of ordinary engine oil.