The invention discloses a method for preparing alfalfa feed for aquarium fishes. Fresh alfalfa is chopped, dried and smashed into alfalfa powder; peanut meal, soybean meal and cottonseed meal are smashed, and corn powder, wheat germ flour, fish meal, shrimp meal, scallop meal, chitosan, zeolite powder and spirulina powder are screened; chicken livers are cooked and cut; traditional Chinese medicine powder is prepared from radix astragali, radix isatidis, perilla leaves and felwort by decocting and extracting, and grinding into powder; the alfalfa powder, the peanut meal, the soybean meal, the cottonseed meal, the corn powder, the wheat germ flour, the fish meal, the shrimp meal, the scallop meal, the chitosan, the zeolite powder and the spirulina powder are mixed, then the traditional Chinese medicine powder, vitamin D, calcium carbonate, ferrous sulfate, lysine and methionine are mixed, finally the chicken livers and soybean oil are added, granulation is conducted after sterilization, and the alfalfa feed for aquarium fishes is obtained. The feed meets the requirement of aquarium fishes for animal protein and plant protein, also meets the requirement for minerals and microelements, quickly promotes growth of aquarium fishes, and improves gloss of aquarium fishes.