The invention belongs to the technical field of pork pig feeds, and particularly relates to a Chinese herbal medicine feed additive for preventing and treating digestive tract diseases of pork pigs and a preparation method of the feed additive. The preparation method comprises the steps that semen raphani, unpolished seeds of Job's tears, aucklandia lappa, medicine terminalia fruit and pericarpium citri reticulatae are sequentially subjected to reflux extraction with 60%-90% ethyl alcohol and potable water, extracted solutions are mixed and then are mixed with water extracts of flower of poplar, herba portulacae, the root of Chinese pulsatilla, poria cocos, cortex magnoliae officinalis, atractylodes macrocephala koidz, sophora japonica, gordon euryale seeds, radix astragali, radix codonopsis, radix scutellariae, rhizoma atractylodis, crataegus pinnatifida and licorice root to obtain a mixed liquid, the mixed liquid is concentrated, dried and processed so as to form dry powder, and finally the dry powder is evenly mixed with crushed fried malt powder and Kelp powder and then packaged. According to the Chinese herbal medicine feed additive, the raw materials are scientific and reasonable, the preparation process is high in operability, and the prepared additive is good in palatability, can effectively prevent the digestive tract diseases of the pork pigs from occurring, promotes the productive performances, anti-stress capacity and immunity of the pork pigs, and improves the quality and nutritive value of pork.