The invention relates to a preparation method of animal feed, and provides a formula of feed capable of meeting the need for protein of partridge and preventing fatty liver of partridge and a preparation method thereof in order to overcome the shortcomings that the existing partridge feed is replaced by chicken feed. The preparation method comprises the following concrete steps of: slicing carrot and cassava, soaking in water together with corn, wheat, cotton seed meal, bran, yellow mealworm and chrysanthemum, grinding, dissolving lysine, methionine, threonine and table salt in warm water, stirring uniformly and standing; adding the ground corn, wheat, cotton seed meal, bran, yellow mealworm, chrysanthemum, carrot and cassava into the fermented liquid, and stirring uniformly; and fermenting, granulating, drying and disinfecting to obtain a finished product. The formula provided by the invention is developed specially according to the raising characteristics of partridge, the preparation technology is simple and easy to operate, and the need for protein of partridge can be met; and the nutrition is comprehensive and balanced, and the problem of fatty liver of the partridge after eating the feed is effectively avoided.