The most important thing before radiotherapy for patients’ breast cancer is functional exercise, so that the activity of the upper limbs on the affected side can meet the requirements of radiotherapy. Because the arm has to be stretched upward during radiotherapy, patients should actively carry out functional exercises after the operation and perform breast rehabilitation exercises under the guidance of doctors and nurses, which is very important for the patients; the second is the condition of the chest wall, the requirements of radiotherapy on the chest wall are that there is no accumulation of gas and fluid under the skin and the incision is healed, so the patients have to actively cooperate with the doctors, and if they have diabetes, they have to strictly control their blood glucose to speed up the recovery of the operated area in order to meet the requirements of radiotherapy. Before radiotherapy begins, the physician will conduct CT simulation and image transmission to outline various target areas and vital organs, and develop the most appropriate radiation treatment plan, which is finally implemented on the patient.