Radiation pneumonitis is a side effect or complication of radiation therapy for lung cancer patients. Depending on the degree of radiation pneumonitis, it is categorized into 6 degrees. Generally speaking, 0 degree has no symptoms and no imaging manifestations; 1 degree has some imaging manifestations but no clinical symptoms; 2 degree has mild symptoms, which can be solved by mild cough suppression; 3, 4 and 5 degree patients are more serious. Moderate and severe radiation pneumonitis requires clinical treatment, usually with hormonal shock therapy. Because radiation pneumonitis is aseptic inflammation, hormone shock is needed, followed by cough suppression, sputum, oxygen inhalation, etc. to control the symptoms as early as possible, so as not to allow it to develop into radiation pulmonary fibrosis.