The invention discloses graphene lubricating oil and a preparation method thereof. The graphene lubricating oil is prepared from the following raw materials: engine oil, rice bran oil, ethylene glycoldipolynaphthenate, cyclohexane, triethanolamine, a silane coupling agent KH-570, octylphenol, 4-hydroxyl-4-methyl-2-pentanone, styrenated phenol, jojoba oil, alkenyl succinate, castor oil polyoxyethylene ether, benzotriazole, cinnamyl alcohol, secondary octanol, polyoxyethylene glyceryl ether laurate, methylisothiazolinone, uracil, carbon black, wax powder, corundum powder, nano silicon dioxide,stearic acid, pentaerythritol, naphthenic acid, ammonium bicarbonate, zinc acetylacetonate, nano graphene, aluminum nitride and an antibacterial agent; the graphene lubricating oil is prepared throughsteps of preparing a base material, preparing a modified material, mixing and the like. The graphene lubricating oil provided by the invention has excellent high-temperature resisting, antirust and antibacterial performance.