The invention discloses an immersion-type heat radiation cooling liquid used for power lithium batteries, and a preparation method thereof, and belongs to the field of chemistry. The immersion-type heat radiation cooling liquid used for power lithium batteries is composed of, by weight, 30 to 70 parts of a hydrofluoroether compound, 30 to 50 parts of a halogenated hydrocarbon, 1 to 10 parts of analcohol compound, 0.01 to 0.5 part of an antioxidant, 0.01 to 0.5 part of a preservative, and 0.01 to 0.5 part of a nano metal oxide. According to the preparation method, the hydrofluoroether compoundis taken as a main component, and is mixed with the halogenated hydrocarbon, the alcohol compound, and the like to form an azeotrope, and the antioxidant, the preservative, and the non-conductive nano metal oxide additives are adopted as auxiliary additives to form the cooling liquid composition. The immersion-type heat radiation cooling liquid is excellent in heat radiation effect, is high in specific heat, low in expansion performance, low in toxicity, high in insulation performance, excellent in flame resistance, inert performance, and material compatibility, is capable of realizing heat transfer effect rapidly, is capable of solving power lithium battery heating and heat radiation problems effectively, prolonging battery service life, reducing failure risk, and improving battery safety performance.