The invention discloses a traditional Chinese medicine preparation for preventing and treating pigling diarrhea and a preparation method thereof, and relates to related technology of granules using traditional Chinese medicinal materials as raw materials for treating pigling yellow and white diarrhea. The traditional Chinese medicine preparation comprises the following components: 10-40g of coptis, 10-40g of pulsatilla, 10-50g of purslane, 10-30g of polygonum hydropiper and 5-50g of carbonized sanguisorba root. The preparation method is as follows: decocting the coptis, pulsatilla, purslane and polygonum hydropiper with water for two times, decompressing for concentrating, drying to obtain dry extractum, smashing, sieving with a 100 mesh sieve to obtain extractum powder A for standby use; crushing the carbonized sanguisorba root, sieving with a 100 mesh sieve to obtain carbonized sanguisorba root powder B; evenly mixing the extractum powder A and the carbonized sanguisorba root powder B, adding an appropriate amount of an excipient, granulating, drying, and packaging to obtain the product.