The invention discloses a method for preparing armillariella fermented feed, and belongs to the technical field of feed, food, medicaments and microorganism fermentation. The method comprises the following steps: mixing five kinds of feed, namely, yeast powder, maltodextrin, cane sugar, glucose, peeled soybean meal, soybean meal and the like, adding water for mixing, sterilizing at high temperature, and inoculating armillariella to ferment so as to obtain an armillariella seed liquid; mixing the feed, namely, corn, bean pulp, extruded soybean, fish meal, plasma protein, whey powder, bran, premix and the like with the armillariella seed liquid, adding water to adjust and ferment, and drying so as to prepare the armillariella fermented feed. The armillariella fermented feed is rich in functional substances of granulose, armillariella laccase, armillarisin B, armillarisin C, armillarisin polypeptide and the like, and has the characteristics of high immunologic function, high nutrition, easiness in digestion, good palatability and the like.