The invention discloses micro-emulsified water-soluble 
cutting fluid and a preparation method thereof. The micro-emulsified water-soluble 
cutting fluid comprises the following components in percentage by weight: 6-15 percent of 
base oil or oiliness agent, 2-5 percent of 
nonionic surfactant, 5-10 percent of anionic surfactant, 5-8 percent of mixed alkylol amine, 10-15 percent of antirust agent, 0.08-0.1 percent of 
copper alloy corrosion inhibitor, 0-0.5 percent of 
ethylenediamine tetraacetic acid tetrasodium salt, 0.1-0.2 percent of antifoaming agent and the balance of water. The micro-emulsified water-soluble 
cutting fluid prepared by the invention is high in cooling property, antirust property and 
hard water resistance and hardly deteriorates or stinks, the product can inhibit fungi, 
bacteria and moulds very well without adding any special bactericide, the service life of the product is prolonged, and harm of the bactericide to 
skin irritation is avoided. The 
cutting fluid is reasonable in formula, multiple surfactants and aids are utilized, the provided 
cutting fluid is diluted with water according to a general ratio of 1:20 before being used, the antirust time of a 
single product exceeds 180 hours, the use of the product is not influenced even if the tank is not replaced within a year according to customer response, the manpower and 
material resources needed in the process of replacing the tank are saved, and the cost is saved.