Rectal intramucosal cancer is also known as rectal intramucosal high-grade neoplasia. Rectal intramucosal high-grade neoplasia refers to pre-cancerous lesions, which have certain chances to develop into cancer, and should be detected and treated as early as possible so as not to delay the condition. Rectal intramucosal cancer is not a cancer clinically, and no lesion is found to invade into the submucosal layer of rectal tumor, but it has the chance to develop into cancer, usually belongs to precancerous lesion. Rectal intramucosal cancer may have symptoms such as change of bowel habit or change of bowel movement, sometimes accompanied by abdominal pain, etc. It needs timely treatment, which can be done by surgical resection of the lesion, and at the same time combining with chemotherapeutic drugs for adjuvant therapy, such as cyclophosphamide and paclitaxel. Patients with rectal intramucosal cancer should eat more food rich in dietary fiber, which can promote gastrointestinal peristalsis and prevent constipation, and is conducive to the recovery of the disease. Meanwhile, they should go to the hospital for rechecking regularly to observe whether there is recurrence or not and give timely treatment.