The invention discloses long-life high-temperature bearing grease which comprises the following raw materials in parts by weight: 12 parts of octadecylamine, 4 parts of cyclohexane, 9 parts of MDI, 10 parts of petroleum calcium sulfonate, 1 part of petroleum ether, 100 parts of base oil A, 70 parts of base oil B, 1.5 parts of an antioxidant A, 0.3 part of an antioxidant B, 1.5 parts of an anti-wear reagent A at extreme pressure, 3 parts of an anti-wear reagent B at extreme pressure, 4 parts of an oiliness agent, 5 parts of a stabilizer, 1 part of a tackifier and 1.5 parts of anti-rust agent. During preparation, the various raw materials are subjected to stirring reaction under the required order according to different temperature and time parameters and treated according to related process requirements. The grease has excellent high temperature resistance, lubricating property, adhesion, water resistance and extreme pressure anti-wear property, excellent shearing resistance, thermal stability and sealing property, as well as excellent oxidation resistance, chemical corrosion resistance and rustproof property and can realize long-life lubrication of each equipment bearing. Moreover, the preparation method is simple, easy to operate, wide in product purposes and good in effect.