The invention provides a compound traditional Chinese medicinal pill for treating bloody stool of pets, and a preparation method thereof. The pill is composed of 60g of Rhizoma Coptidis and 60g of Fructus Aurantii (120g of sophora flower is simultaneously stir-fried and then is removed). Effective components of the above medicines are respectively extracted through a certain technology. Rhizoma Coptidis is minced, and obtained steamed cakes are processed to obtain the pill. The method is simple and reasonable, and allows the pill with convenient use and long period of validity to be obtained. The pill has good curative effect and wide indication, is safe, effective and stable to pets, and can be conveniently used by the pets.