The low-temperature viscosity of anhydrous coolant is reduced by adding ethylene glycol to the propylene glycol base fluid, and the evaluation method of low-temperature fluidity is also studied. The experimental results show that the low-temperature fluidity of anhydrous coolant can be greatly improved by the participating of ethylene glycol. Freezing point method is usually used for measuring the low temperature performance of coolant, but for “long icing process” anhydrous coolant, beginning-crystal point shows more practical reference value. Therefore, freezing point, beginning-crystal point and low-temperature fluidity should be considered at the same time when evaluation the low temperature performance of anhydrous coolant.