The first thing is to diagnose middle differentiated adenocarcinoma of the rectum. After having symptoms or during physical examination, colonoscopy should be done, which is the gold standard for diagnosing colon cancer and rectal cancer, while pathology should be done. Treatment includes the following aspects: 1. MRI, CT and ultrasound are done to make the best plan for treatment. MRI and CT can clarify lymph node metastasis and whether there is distant metastasis. 2. Surgery is preferred after tumor discovery, and radiotherapy after surgical removal of tumor is beneficial to patients’ prognosis. 3. Stage III and IV patients with late discovery can choose neoadjuvant radiotherapy treatment. Above the rectum, neoadjuvant chemotherapy is the main treatment, and below the rectum, neoadjuvant radiotherapy is the main treatment. Through neoadjuvant treatment, the tumor can be reduced in stage, that is, the original stage IV becomes stage III, stage III becomes stage II, and the tumor can be reduced in size, which is conducive to complete surgical resection. Its treatment needs to be strictly determined according to pathological staging and clinical stage to determine the best plan, or individualized treatment plan. MDT multidisciplinary combined treatment approach is advocated for the treatment of mesodifferentiated adenocarcinoma of the rectum, where each different patient chooses a different regimen for treatment, so that patients can get the maximum benefit.