The invention discloses a preparation method of a feed for improving the milk yield of cows. The preparation method comprises the steps that ricepaperplant pith, corn meal, cottonseed meal, wheat straw, wheat, oats, corn stalks, peanut vines, black beans, anises, Chinese prickly ash, Chinese prickly ash leaves, brewer's grains, dried banana powder, dried apple powder, siraitia grosvenorii and dried honeycombs are adopted to prepare a first feed; yellow mealworms, protein powder, chicken, spirulina powder, oyster powder, endothelium corneum gigeriae galli, crab shells, boneless pig's feet, crucian carps and dried small shrimps are adopted to prepare a second feed; papain, xylanase, alpha-galactosidase, folic acid, cod liver oil, a vitamin A, a vitamin B, carotene and a vitamin E are mixed to prepare a third feed, and the first feed, the second feed, the third feed and EM probiotics are mixed according to the mass ratio of 4:2:0.7:0.08 to obtain the feed for improving the milk yield of the cows. The preparation method is simple, and the prepared feed is rich in nutrition.