The invention belongs to the technical field of metal cutting fluids, and particularly relates to a graphene-synergized discharge-free environment-friendly water-based cutting fluid and a preparationmethod thereof. The graphene-synergized discharge-free environment-friendly water-based cutting fluid comprises the following components in percent by mass: 5-18% of a lubricating agent, 4-12% of an antirust agent, 0.05-0.15% of an anti-hard water agent, 2-5% of a corrosion inhibitor, 0.5-1.5% of an antioxidant, 1-2% of an anti-foaming agent, 0.5-4% of an anticorrosion and bactericidal agent, 3-12% of a graphene dispersion liquid and 83.95-45.35% of water. The graphene-synergized discharge-free environment-friendly water-based cutting fluid has relatively good wear resistance and lubricating performance, and the cooling performance and the antirust performance of the water-based cutting fluid are improved, so that the water-based metal cutting fluid has a wider application prospect; in addition, used materials are environmentally friendly, so that environment pollution is reduced.