Provided is a chloride-free extreme pressure microemulsion cutting fluid. The cutting fluid is prepared from the following raw materials, by weight, 4-5 parts of boric acid, 1-2 benzotriazole, 1-2 parts of octyl decanoic acid, 1-2 parts of lauryl sodium sulfate, 3-4 parts of polyacrylamide, 2-3 parts of urea, 0.8-1.2 parts of span 40, 0.5-1 part of lanthanum nitrate, 12-15 parts of kerosene, 6-8 parts of auxiliary agents and 200 parts of water. The cutting fluid contains no harmful substances of sodium nitrite, phenol, chlorine, mercury and the like, and is safe and environmentally friendly. Through application of boric acid and lanthanum nitrate, the cutting fluid has excellent extreme pressure performances, and workpieces are not easy to damage. The cutting fluid is advantaged by stable emulsification, no delamination, no coacervation, long service time and low cost. The cutting fluid is suitable for processing of a plurality of materials such as cast iron, steel, aluminum, copper, magnesium alloy and the like, and can meet a plurality of processing technology requirements of turning, drilling, grinding, center processing and the like.