The invention provides a graphene cutting fluid and a preparation method thereof. The graphene cutting fluid is prepared from the following components in percentage by weight: 12%-25% of polyether, 10%-18% of borate, 2%-8% of an amine compound, 1%-8% of an antioxidant, 1%-8% of oleic acid, 5%-15% of a polybasic acid rust preventive, 0.2%-2% of a settling agent, 1%-8% of a graphene diluent, and thebalance of water. Compared with the prior art, polyether composite graphene is used as a lubricant, and meanwhile an ester additive is added and is used as an auxiliary, so that the graphene cuttingfluid has high lubricating performance; the polybasic acid rust preventive is adopted as an environment-friendly aqueous rust preventive, so that the damage of a traditional sodium nitrite rust preventive to a human body is avoided; the settling agent can effectively solve the problem that a metal or processing material is suspended, without settling in the processing process, the cutting fluid ispurified, and the abrasion resistance of a processing fluid is improved; the graphene cutting fluid is high in cost performance, environmentally friendly, and simple in water treatment, does not directly pollute environment, has high lubricating performance, can directly replace cutting oil, and saves oil resources; and the preparation method is simple, low in cost and suitable for large-scale popularization and application.