The invention discloses a method for modifying a water-based lubricating fluid with wood flour-soybean lecithin. The method comprises the following steps: putting wood flour into a high-speed mixer, adding KH550 for treatment, adding a potassium hydroxide solution, stirring, standing, washing with water to neutrality, drying, and pulverizing to obtain composite modified wood flour; heating soybeanlecithin, introducing nitrogen gas, stirring, adding lactic acid and hydrogen peroxide, and reacting at constant temperature to obtain hydroxylated modified soybean lecithin; adding dispersing agentlauryl sodium sulfate into deionized water, heating, stirring and dissolving, adding antirust agent triethanolamine, antifoaming agent dimethicone, the composite modified wood flour and the hydroxylated modified soybean lecithin under thermal insulation conditions, carrying out strong stirring, adjusting the pH value, adding ferrous carbonate, polyhydroxylation modified graphene oxide and surfacemodified carbon fibers, carrying out strong stirring for surface modification and dispersion, and carrying out ultrasonic oscillation in a water bath to obtain the water-based lubricating fluid.