The invention belongs to the technical field of research on feed additives, and particularly relates to a traditional Chinese medicine feed additive for treating poultry diarrhea and a preparation method of the traditional Chinese medicine feed additive. The traditional Chinese medicine feed additive for treating poultry diarrhea is prepared from, by weight, 30-45 parts of selfheal, 25-35 parts of oyster, 25-30 parts of codonopsis pilosula, 18-25 parts of toasted sanguisorba officinalis, 15-30 parts of Chinese brake herb, 15-30 parts of fruticose breyniae leaf and twig, 25-30 parts of flat peach leaf buds, 15-25 parts of purslane, 10-15 parts of lotus leaves, 10-15 parts of lotus petiole, 10-15 parts of lotus leaf bases and 20-35 parts of parched rice. The raw materials have a synergistic interaction effect, and the traditional Chinese medicine feed additive has the effects of strengthening the spleen and stomach, achieving astriction for detoxication, promoting blood circulation for removing wind and promoting digestion, and particularly has a remarkable effect on stopping dysentery, recovering gastrointestinal function and maintaining normal digestive system functions; the formula composition is simple, the cost is low, the treatment time is short, and a special effect is achieved for treating poultry diarrhea.