Preoperative neoadjuvant radiotherapy for rectal cancer is divided into short-acting and long-acting, short-acting in about 5 days and long-acting in about 25 days. Rectal cancer is a malignant tumor originated from rectal mucosal epithelium. If it is locally advanced rectal cancer, for patients who can undergo surgery, it is recommended to do neoadjuvant radiotherapy first to reduce the size of the tumor, so as to reduce the difficulty of surgery and the possibility of recurrence. Preoperative neoadjuvant radiotherapy for rectal cancer can be divided into short-acting and long-acting. Preoperative short-acting radiotherapy will be administered in about 5 days, and surgery will be performed within 1 week after the end of the treatment. The preoperative long course of radiotherapy is about 25 days, and surgery will be performed 6~8 weeks after the end of the course. Preoperative neoadjuvant radiotherapy for rectal cancer can control and shrink the tumor, strive for radical resection, and improve the survival rate of patients, patients should actively cooperate with doctors to carry out relevant treatment and improve the prognosis. Keep a good mood during treatment and avoid excessive pressure.