The invention discloses a preparation method of a water base graphite antirust cutting fluid, and relates to the technical field of industrial lubricant. The preparation method comprises the following steps: step one, preparing the following raw materials in percentage by weight: 12 to 18% of flake graphite powder with a size of 800 to 1000 meshes, 3 to 5% of triethanolamine oleate, 1 to 4% of phenolic hydroxyl modified silicone oil, 1.5 to 3% of nano cubic boron nitride particle, 2 to 5% of cetyl dimethyl ammonium bromide, 2 to 4% of dimer acid potassium, 0.5 to 2% of aqueous antifoaming agent, and the balance being deionized water; and step two, preparing a proper amount of deionized water at a room temperature under a normal pressure, at first, adding nano cubic boron nitride particles, flake graphite powder with a size of 800 to 1000 meshes, and triethanolamine oleate into the deionized water, carrying out ultrasonic emulsification for 40 to 50 minutes, then adding phenolic hydroxyl modified silicone oil, cetyl dimethyl ammonium bromide, dimer acid potassium, an aqueous antifoaming agent, and residual deionized water, and stirring to evenly mix all components. The preparation method has the advantages that the kinds of used raw materials are few, and the prepared water base graphite antirust cutting fluid has an excellent performance on resisting extreme pressure, wear, and rust.