A liquid lubricating antifriction repairing agent for a wheel/rail having the effects of lubrication, friction prevention and in-situ repair comprises 50-60 parts of resin, 40-50 parts of curing agent, 5-10 parts of grease, 6-15 parts of sub-nanometer scale silicate powder, 4-10 parts of lubricant and 0.05-0.2 part of coupling agent. A method for preparing the liquid lubricating antifriction repairing agent for the wheel/rail is further provided, and the method comprises the following steps of: (1) preparing the resin, the curing agent, the grease, the sub-nanometer scale silicate powder, the lubricant and the coupling agent in accordance with proportions according to claim 1; (2) covering the sub-nanometer scale silicate powder with the coupling agent at a covering temperature ranging from 80 to 90 DEG C; (3) mixing the curing agent with the grease; (4) mixing the substance obtained in the step (2) with the mixture obtained in the step (3); (5) mixing the lubricant with the mixture; (6) mixing the resin with the mixture, wherein the time of mixing the resin is controlled within 15-20 minutes; and (7) pouring the mixture in a die for curing and formation. The repairing agent can be coated on the rim of the wheel through a filler.