The invention relates to a culture medium for wild-taste pleurotus eryngii and a preparation method of the culture medium. The culture medium comprises the following components in percentages: 57.5% of peanut vines, 22.5% of cottonseed hulls, 17.5% of potatoes, 0.25% of sucrose, 0.15% of quicklime, 0.3% of slaked lime, 0.25% of calcium superphosphate, and 0.225% of magnesium sulfate. According tothe method disclosed by the invention, in the preparation process, the ground potatoes are immersed into hot water with a water temperature of higher than 50 DEG C, quick stirring is performed, the amount of hot water can be ensured that a potato liquid is in a dilute and thin paste state after the potatoes are fully dissolved and expanded and cooled to normal temperature, the cottonseed hulls harvested in a current year are put into a retting pond, a certain amount of water is added, the retting pond is kept relatively sealed, the environmental temperature in the retting pond is 32 DEG C or more, retting is performed, the potatoes and the cottonseed hulls are mixed with the fermented peanut vines, so that nutrient ingredients are decomposed and easier to absorb; the sucrose, the quicklime, the slaked lime, the calcium superphosphate and the magnesium sulfate are sprayed on the surface of the culture medium, so that absorption and growth of the pleurotus eryngii are facilitated; and the peanut vines facilitate improving the wild taste of the pleurotus eryngii.