The present invention discloses a preparation method of a donkey feed. The donkey feed comprises the following raw materials: 40-50 parts of corn, 20-30 parts of wheat, 10-15 parts of soybean meal, 30-40 parts of ryegrass, 15-20 parts of pumpkin vines, 5-10 parts of tofu dregs, 4-6 parts of stone powder, 5-7 parts of an attractant, 1-2 parts of fermentation liquid, 0.5-1 part of sodium bicarbonate, 0.3-0.5 part of edible salt, and 3-5 parts of vegetable oil. During the preparation, the corn, wheat, soybean meal, ryegrass, pumpkin vines, and tofu dregs are crushed, then the crushed raw materials are mixed with the fermentation liquid, the mixture is subjected to a sealed fermentation, the obtained fermented materials are mixed evenly with the stone powder, attractant, sodium bicarbonate, edible salt and vegetable oil, and the mixture is sent into a granulator to conduct granulation. The feed prepared by the method contains various needed nutrition for the growths of donkeys, ensures the healthy production at the same time, also provides the health-care values, and improves the growth speed of the donkeys.