Abstract: Radiation-induced lung toxicity (RILT),caused by lung, esophageal thoracic tumor radiation therapy, the common and serious side effects, include the early acute radiation pneumonia and late radiation pulmonary fibrosis. Because the lungs are sensitive to radiation, radiation damage may occur when they receive a certain dose of radiation. At present, the mechanism of radioactive lung toxicity is still unclear, and there is a lack of effective prediction indicators and treatment measures, which not only limits the radiotherapy dose of tumor, but also seriously affects the follow-up treatment and quality of life of patients, becoming a bottleneck to improve the efficacy of radiotherapy for chest tumor. Recent studies have found that radioactive lung toxicity is not only closely related to the exposed dose and volume of the lung, but also related to the expression and signal transduction of various cytokines, such as inflammatory cell infiltration, inflammatory cytokine imbalance, and oxidative injury, which are all involved in the pathogenesis of radioactive lung toxicity. In addition, the patient's physical condition is also related to the occurrence of radioactive lung toxicity. Therefore, the occurrence of radioactive lung toxicity is a complex process of interaction of many factors. At present, antibiotics and glucocorticoids are mainly used in clinical treatment of lung radiation inflammation, but the overall effect is not good. Because of the lack of effective prevention and treatment of radioactive pulmonary fibrosis, so the mechanism of radioactive lung toxicity and clinical prevention and treatment research is of great significance. In recent years, the research on radioactive lung toxicity has become a hot spot. People have made more in-depth research on the mechanism of radioactive lung injury and made certain breakthroughs in clinical prevention and treatment, such as the application of cytokine inhibitors, gene therapy, Chinese and western medicine, stem cell transplantation, etc. This article reviews the mechanism, clinical factors and clinical prevention and treatment of radioactive lung toxicity.