The five-year survival rate of lung cancer patients after radiotherapy can range from 5% to 70%, which is highly related to the clinical stage. Lung cancer is a common malignant tumor of the respiratory system, and the occurrence of the disease is related to smoking, heredity, environment and other factors. Radiotherapy is a therapy using high-energy rays to kill tumor cells, which can be used for postoperative adjuvant treatment and palliative treatment for patients with no chance of surgery in advanced stage. It is often combined with radiotherapy and targeted therapy. Radiotherapy can be used in the treatment of early, middle and late stage of lung cancer. Therefore, after treatment, the five-year survival rate of patients is more related to the stage. The five-year survival rate of early stage lung cancer patients is about 70%; middle stage can be about 15%~50%; advanced stage can be only 5%.