Generally small cell lung cancer can be treated by radiotherapy, but radiotherapy is not recommended for patients with very early, extensive and advanced small cell lung cancer with poor physique. Radiotherapy is a commonly used method in the comprehensive treatment plan for small cell lung cancer. Especially when the tumor location of small cell lung cancer is not suitable for surgery, radiotherapy can be used to kill the tumor cells, relieve the pain and other discomforts of the patients with small cell lung cancer, and achieve good therapeutic effect. However, radiotherapy is not recommended for all small cell lung cancer patients, like very early stage small cell lung cancer patients, when there is no metastasis, they can be removed by surgery; extensive stage small cell lung cancer, it is more suitable to use immunotherapy and chemotherapy combined treatment plan; advanced stage small cell lung cancer patients with poor physical condition and multiple complications are not suitable for radiotherapy plan. Small cell lung cancer patients should go to regular hospitals in time, and doctors should determine the treatment plan by combining their conditions.