Lung cancer is the most common cause of the death from cancers for both male and female in the world. Surgery remains the most effective method for controlling the primary tumour in most cases, but only 20% primary lesions can be resected. 80% patients should be treated by non - surgical methods. In recent years, radiotherapy has a fast development in the equipment and especially in the theory of radiobiology, but the curability of lung cancer still poor. In this paper we discussed the radiotherapy of lung cancer and how to choose the energe of X - ray, design the fields; the proceeding of irradiation; and it is necessary to find out a new regulation for stages that is available to indicate non - surgical treatment.
