It is difficult to achieve cure with radiotherapy in limited stage of small cell lung cancer, and it is recommended to carry out simultaneous radiotherapy and chemotherapy. The limited stage of small cell lung cancer is based on the American Legion Lung Cancer Association staging standard, which indicates that the tumor is still confined to one side of the chest cavity, or there are metastases in adjacent lymph nodes, accompanied by symptoms of pleural effusion, and it is difficult to control the disease and achieve a cure by radiotherapy alone. Simple radiotherapy is difficult to control the disease and achieve a cure. Synchronized radiotherapy is the preferred treatment option for small cell lung cancer in limited stage, and some of them can achieve a clinical cure; however, most of them can only prolong the survival period and improve the quality of life.