The best time for breast cancer radiotherapy is as follows: 1, breast cancer patients who need chemotherapy: radiotherapy can be started after chemotherapy is finished for 2-3 weeks and the general condition of the body is recovered, and it is recommended that the patients should have radiotherapy within half a year; 2, patients who have breast-conservation in the early stage of breast cancer or patients who don’t need postoperative adjuvant chemotherapy are recommended to start radiotherapy when the wound has been recovered well in 3-4 weeks after the operation, and the radiotherapy shouldn’t be started more than 8 weeks after the operation; 3, patients who have adjuvant chemotherapy for more than half a year after the operation due to their physical condition and tolerance, and the adjuvant radiotherapy is still necessary if the chemotherapy is continuously maintained.