Stage III moderately differentiated rectal cancer belongs to one of the moderately malignant rectal tumors, the specific etiology of which is not clear at the moment, and it may be related to daily dietary habits, heredity, immunity and so on, resulting in repeated stimulation of rectal mucosa, damage, mutation and so on, and localized lymph node metastasis has already occurred. Stage III moderately differentiated rectal cancer means that 25-75% of the cancer cells are well differentiated and moderately malignant, with local lymph node metastasis and some infiltration with the surrounding tissues, which requires further examination, such as colonoscopy, CT examination, etc., to observe the degree of infiltration and determine the specific treatment plan. Due to the localized lymph node metastasis, the third stage of the disease cannot be cured by surgery alone, and radiotherapy is needed to achieve a better therapeutic effect. In daily life, pay attention to light diet, avoid spicy diet on rectal mucosa repeated damage stimulation, pay attention to local cleanliness and hygiene after defecation. Actively cooperate with the treatment, and strive to control and stabilize the condition and improve the quality of life.