Abstract: Radiation-induced lung injury (RILI) is a common complication of chest radiotherapy, while its pathogenesis is still unclear. According to the latest research, immune microenvironment plays an important role in the occurrence and development of RILI. Therefore, the authors conducted a systematic review on the alterations in the pulmonary immune microenvironment following chest irradiation and the role of these changes in RILI, aiming to provide a theoretical basis for elucidating the pathogenic mechanisms of RILI and developing prevention and treatment strategies.