The invention discloses a high-temperature-resistant lubricating agent, comprising 20-60 parts of vegetable oil, 30-70 parts of sulfonated bitumen and 0-30 parts of sulfonated vegetable oil by mass. The high-temperature-resistant lubricating agent for drilling fluid disclosed by the invention is strong in temperature resistance and high-efficient in performance; the friction and the torque of a drilling tool can be significantly reduced, and the lubricating property of the drilling fluid is improved when the high-temperature-resistant lubricating agent is applied to water-based drilling fluid.