The invention provides a preparation for preventing crops from frost damage. The preparation comprises the following components in parts by weight: 2-5 parts of paraffin, 5-8 parts of edible oil, 4-8 parts of isobutene, 3-9 parts of fulvic acid, 5-9 parts of heteroauxin, 2-6 parts of allium sativum oil, 2-5 parts of monobasic organic acid, and 2-5 parts of a cooking liquor of szechuan lovage rhizome, fructus evodiae, dry eggplant stems and rhizoma zingiberis, wherein the ion content of Cu, Fe, Mn, Zn and B in the preparation is greater than or equal to 95 g/L. The preparation provided by the invention is simple in ratio and convenient to use, can greatly reduce frost damage to trees, is good in freeze-proof effect, can activate a biological enzyme, prevents the generation of an ice nucleating bacteria, destroys ice generation activity of frozen protein by increasing heat quantity, reduces a freezing point of a plant cell, accelerates the flow of cellular plasm, improves the activity of the cell by 4-8 times, increases the water-holding and drought-resisting capacity of plants, reduces frost damage, can alleviate and cure moderate and light frost damage to the plants, is ineffective on heavy frost damage, and reduces the freezing point value of the plants by 5-8 DEG C.