The invention provides feed for improving the anti-diarrhea ability of piglets and a preparation method thereof. The feed comprises, by mass, 30 to 50 portions of pregelatinized rice, 5 to 10 portions of expanded corn, 5 to 10 portions of pea protein powder, 5 to 20 portions of flour, 5 to 20 portions of expanded soybean, 1 to 5 portions of super steam dried fish meal, 1 to 3 portions of fish soluble powder, 5 to 15 portions of whey powder, 1 to 3 portions of vegetable oil, 0.3 to 0.8 portions of calcium carbonate, 0.5 to 1 portion of calcium dihydrogen phosphate, 0.1 to 0.4 portions of sodium chloride, 0.95 to 2.2 portions of amino acids and 0.3 to 0.8 portions of drug feed additives. The drug feed additives include pilose asiabell root, radix astragali, white atractylodes rhizome, white peony root, licorice root, poria cocos, radix angelicae sinensis, ligusticum wallichii, plantain seed, wild buckwheat and dandelion. The feed improves piglet intake, promotes growth, enhances immunity, reduces a diarrhea rate, promotes digestive organ development, improves enzyme activity and improves animal product quality.