Objective,2,To analyze the tongue image features of patients with ulcerative colitis (UC) and explore the relationship between the tongue images and the colonoscopic features based on image data processing., Methods,2,A total of 226 confirmed UC patients and 45 health people were selected as study subjects. The tongue image indexes of all study subjects were collected and analyzed by TDA-1 tongue diagnosis instrument and TDAS 2.0 Chinese medical tongue diagnosis analysis system, the colonoscopy reports of UC patients were also compiled and recorded, and the tongue image characteristics and the correlation between colonoscopic features and tongue images were analyzed.,Results,2,The tongue image indexes indicated that UC patients especially those with intestinal lesions had redder, more purplish-red, bluer tongue bodies and more yellowish, greasier tongue coatings than the health people. The UC patients with intestinal lesions showed redder, more purplish-red, bluer tongue bodies and more yellowish, greasier tongue coatings than those without lesions recently, but the differences between different locations of intestinal lesions were not significant. As to the degree of congestion and edema, those with intestinal diffuse hyperaemia had redder, more purplish-red tongue bodies and more yellowish, greasier tongue coatings than patients with other types. As to the degree of mucosal frangibility, pus secretion and spontaneous bleeding, the UC patients with intestinal frangibility-positive, pus-positive and spontaneous bleeding-positive had redder, more purplish-red tongue bodies, more yellowish and greasier tongue coatings than those negative individuals. As to the degree of mucosal ulceration, those with mucosal ulceration had redder, more purplish-red tongue bodies and greasier tongue coatings than those without ulceration, and those with diffuse colonic ulcer had more yellowish and greasier tongue coatings than those with other types of UC. The closer the grade between the degrees of ulceration was, the less significant the differences would be, but the overall trend showed that the more severe the degree of ulceration was, the more reddish, purplish-red the tongue bodies and the more yellowish, greasier the tongue coatings would be. Correlation analysis showed that the more severe the degree of intestinal mucosal hyperaemia, frangibility, ulceration, pus secretion, and spontaneous bleeding was, the more reddish and purplish-red the tongue bodies and the more yellowish and greasier the tongue coatings would be; the more extensive the lesion was, the more reddish and purplish-red the tongue bodies and the greasier the tongue coatings would be.,Conclusions,2,Patients with UC are more likely to have red, purplish-red, blue tongue bodies and yellowish greasy tongue coatings compared to healthy individuals. There is a correlation between tongue images and colonoscopic features in UC patients; the more severe the colonoscopic manifestations are, the more reddish and purplish-red the tongue bodies and the more yellowish greasier the tongue coatings would be.