The invention discloses auto cooling fluid, comprising the following raw materials in parts: 10-18 parts of diethylene glycol, 11-14 parts of oxalic acid, 13-15 parts of 1,2-propylene glycol, 12-15 parts of ethylene glycol ethyl ether acetate, 8-12 parts of triethyl phosphonoacetate, 8-12 parts of glufosinate-ammonium, 5-8 parts of N-(phosphonomethyl)iminodiacetic acid, 6-8 parts of styrene-acrylic-triazole, 6-7 parts of 1-hydroxybenzotriazole, 6-9 parts of benzotriazole, 2-3 parts of dimeticone, 1-3 parts of hydroxyl silicone oil, 3-4 parts of a dimethyl silicone polymer, 3-5 parts of butanol, 1-3 parts of sodium hydroxide, 2-3 parts of sodium peroxide, 2-4 parts of potassium chlorate, 1-3 parts of silver carbonate, 2-5 parts of silver phosphate and 150-160 parts of purified water. The auto cooling fluid has good stability, the microbial flora can be inhibited and killed, floccules, flotage, sediments and the like are prevented, effective circulation of the cooling liquid is ensured, the fault of a cooling liquid circulating system is relieved and prevented, the anti-corrosion effect is good, corrosion to the cooling liquid circulation system can be reduced and delayed, the fault of the cooling liquid circulating system is reduced, and the service life of the auto cooling liquid is prolonged.