The invention discloses a concentrated supplementary food capable of improving palatability and resisting diseases for calves, as well as a preparation method and application of the concentrated supplementary food. A formula of the concentrated supplementary food comprises 5-15 parts of puffed cereals, 10-20 parts of steam tabletting cereals, 3-6 parts of middling, 8-15 parts of fermented soybean meal, 30-45 parts of corn, 10-18 parts of soybean meal, 5-15 parts of puffing soybeans, 1.5-3.5 parts of calcium hydrogen phosphate, 0.8-1.5 parts of stone powder, 0.5-1 part of sodium chloride, 0.02-0.03 part of monensin sodium, 0.02-0.03 part of zinc bacitracin and 0.8-1.2 parts of a 1% calf premix. According to the concentrated supplementary food and the preparation method and application thereof disclosed by the invention, raw materials which are high in the content of effective fibers and high in the content of digestible protein, such as the steam tabletting cereals, the puffed cereals and the fermented soybean meal are added, and the middling is added, so that the granular sensation of a feed is improved, the palatability of the calves is met, and minerals, trace elements and vitamins are strengthened; besides, a feed additive for enhancing immunity is added, so that the palatability can be improved, the development level of rumens can be increased, the food consumption and the daily gain of the calves are increased, the disease resistance of the calves can be enhanced, the feed cost can be reduced, the breeding period of replacement cattle can be shortened, the milk production of cows can be increased, and the economic benefits can be increased.