Previously, radiotherapy was the main choice of treatment for esophageal cancer patients other than surgery. Compared with chemotherapy, radiotherapy has less side effects, is less restricted by important organs and tissues around the esophagus than surgery, and has a wider scope of application than surgery. 80% of esophageal cancers can be cured by a combination of radiotherapy and other means. The traditional treatment for esophageal cancer is still surgery. Generally speaking, surgery is mainly used for patients with early to mid-stage esophageal cancer, which only accounts for one-third of all esophageal cancer patients, that is, two-thirds of patients are not suitable for surgery due to the late stage of the disease. According to the purpose of radiotherapy, esophageal cancer can be divided into radical radiotherapy, preoperative radiotherapy and postoperative radiotherapy. Radical radiotherapy is to use radiotherapy alone to cure esophageal cancer. Generally, the dose of radical radiotherapy can achieve the same effect as surgery; preoperative radiotherapy can shrink the tumor and improve the resection rate and survival rate of surgery; postoperative radiotherapy is generally applied to those whose tumor has invaded the outer membrane of esophagus and those whose lymph nodes have metastasized, and the local recurrence rate of such patients is higher, so they should have regular radiotherapy to reduce the recurrence rate and prolong the survival period. Therefore, radiotherapy should be scheduled to reduce the recurrence rate and prolong the survival period at the same time. At present, in developed countries such as Europe, America and Japan, early-stage esophageal cancer can be treated with modern radiotherapy or surgery, while for upper-stage esophageal cancer and advanced esophageal cancer that cannot be operated, the only standard treatment is modern radiotherapy. Many patients do not understand that modern radiotherapy is a comprehensive treatment with high technological content. As far as radiotherapy itself is concerned, it contains the most advanced radiotherapy technology in the world, which can precisely target the location of tumor and the invasion area, and also precisely project the radiotherapy dose to the tumor, minimize the irradiation of normal tissues around the tumor, achieve precise location, precise planning, precise irradiation, and precisely remove all tumor cells. In the early stage of the disease, if patients can receive concurrent radiotherapy, it can increase the efficacy twice. Numerous clinical studies have shown that the efficacy of applying modern radiotherapy techniques plus concurrent radiotherapy to treat esophageal cancer is almost equal to that of surgery.