Colonic capillary dilatation is a manifestation of submucosal arteriovenous malformations of the colon. Colonic capillary dilatation is a relatively rare colon disease, the specific etiology of the majority of patients is not clear, but usually considered to be hereditary capillary dilatation, as well as congenital arteriovenous anomalies have a great deal to do with. Clinical symptoms include painless acute and chronic bleeding in the lower gastrointestinal tract. For the treatment of colonic capillary dilatation, colonoscopic electrocoagulation or argon plasma coagulation laser treatment is generally preferred. However, if there is a large amount of bleeding in the colon that cannot be endoscopically examined, angiographic subembolization or indwelling catheter injection of pressor therapy may be considered. Therefore, if the patient has colonic capillary dilatation, he/she should go to the hospital for treatment in time and choose the suitable way of treatment under the guidance of specialized doctors.