The invention discloses a high-temperature chain lubricant and a preparation method thereof. The high-temperature chain lubricant is composed of the raw materials of, by weight: 70-90 parts of base oil, 10-20 parts of calcium petroleum sulfonate, 0.1-0.3 parts of ethanol, 0.4-0.8 parts of petroleum ether, 1-2 parts of fatty acid, 0.4-0.8 parts of boric acid, 0.6-1 part of water, 1-2 parts of calcium hydroxide, 0.5-1 part of calcium carbonate, and 0.2-0.5 parts of a high-temperature antioxidant. The high-temperature chain lubricant preparation method comprises the steps that: base oil accounting for 30-40% of the total amount of the base oil, calcium petroleum sulfonate, ethanol, petroleum ether, fatty acid, boric acid, water, and calcium hydroxide are sequentially added and are subjected to a saponification reaction; and calcium carbonate and the rest of the base oil are added for refining. The lubricant provided by the invention has excellent high-temperature thermal stability, excellent anti-oxidation stability, good lubrication performance, good permeability, good extreme-pressure wear resistance, and good adhesion. The preparation method is simple and easy to operate.