The invention relates to a water-soluble cutting fluid which is prepared from the following components in percentage by weight: 4% of boric acid, 1% of dodecanedioic acid, 0.1% of benzotriazole, 7% of triethanolamine, 4% of isopropanolamine, 6% of tall oil, 3% of tetramerization ricinoleic acid, 3% of petroleum sodium sulfonate, 36% of mineral oil, 5% of synthetic ester, 0.5% of an aluminum corrosion inhibitor, 2% of an MBM bactericide, 2% of an emulsifier and 26.4% of water. The pH value of the prepared water-soluble cutting fluid is controlled between 8.3 and 9.3; skin allergy is caused to a certain extent when the pH value is over-high; and the anti-rust capability and the antibacterial ability of the cutting fluid are affected when the pH value is over-low. The MBM bactericide is capable of prolonging the service life of the water-soluble cutting fluid. The formula is simple and convenient to use; the anti-oxidation ability and the anti-rust capability of non-ferrous metals are improved when applied to the non-ferrous metals; and the service life of non-ferrous metal equipment is prolonged.