Ulcerative colitis is a chronic nonspecific colitis, mainly affecting the rectum and colon, with lesions mainly confined to the mucosa and submucosa of the large intestine, with abdominal pain, diarrhea, and pus and blood in the stool as the main manifestations. The exact mechanism of pathogenesis is unknown, and may be related to abnormal immune function, infection, genetics, etc. The diagnosis is mainly based on colonoscopy and pathological examination. According to the latest research, the relationship between disease duration and cancer rate is 1%-5% for 10 years, 5%-25% for 20 years, and 9%-42% after 30 years. Therefore, ulcerative colitis in the elderly should be correctly understood and actively treated to prevent its cancer, specifically the following aspects should be done: First, formal treatment. Patients diagnosed with the disease should adhere to formal drug treatment, which has a long treatment period and is prone to recurrence. Some patients with long duration of the disease change the dosage of medication or even stop taking medication on their own, resulting in recurrent inflammation, spread and continuous stimulation of the gastrointestinal tract, resulting in adverse consequences and increasing the risk of cancer. For some patients with long duration, extensive lesions, heavy disease and poor effect of drug treatment, surgery can be considered. Second, regular review. Regular review can detect cancerous lesions at an early stage, guide the treatment and reduce the death rate of cancer. For patients with ulcerative colitis, regular screening must be conducted 8-10 years after the onset of the disease. The method is to perform a full colonoscopy every one to two years, and to take biopsies from suspicious areas for pathological examination, and to take corresponding measures according to the examination results. At the same time, fecal occult blood test and serum carcinoembryonic antigen (CEA) examination can be performed regularly. Thirdly, we should be alert to some “alarm symptoms” of tumor, such as increased abdominal pain, poor appetite and unexplained weight loss during the course of the disease; or recurrent blood in stool, which cannot be improved by treatment; or long-term medical treatment is ineffective or the symptoms are not relieved significantly, recurrent attacks, short intervals between attacks and rapid development of the disease. Rapid development of the disease. If these symptoms appear, you should go to the hospital immediately to rule out the possibility of cancer. Especially for patients with a history of more than 10 years, it is important to pay attention to them.