The invention provides a traditional Chinese medicine composition for treating ulcerative colitis and a preparation method thereof, belonging to the field of traditional Chinese medicines. The traditional Chinese medicine composition is prepared from the following raw medicines in parts by weight: 10-30 parts of drynaria, 10-30 parts of raw semen plantaginis, 10-30 parts of fried semen plantaginis, 10-20 parts of raw hawthorn, 10-20 parts of fried hawthorn and 4-6 parts of myrobalan. The composition provided by the invention fully adopts Chinese herbal medicines for formulating, does not havetoxic side effects generated by applying Western medicines for a long time, and fills up the blank of the modern traditional Chinese medicines for effectively treating ulcerative colitis. The prepared new composition has the advantages of novel and refined formulation, exact treatment effect, simple and easy process, high bioavailability and the like, and is convenient to take and carry.