Objective Radiation-induced lung injury(RILI) is the most common,dose-limiting complication in thoracic malignancy radiotherapy.Considering its negative impact on patients and restrictions to efficacy,the mechanism of RILI was studied. Methods Wistar rats were locally irradiated with a single dose of 0,16,and 20 Gy to the right half of the lung to establish a lung injury model.Two and six months after irradiation,the right half of the rat lung tissue was removed,and the concentrations of TGF-β1,angiotensinⅡ,and aldosterone were determined via enzyme-linked immunosorbent assay. Results Statistical differences were observed in the expression levels of angiotensinⅡand aldosterone between the non-irradiation and irradiation groups.Moreover,the expression level of the angiotensinⅡ-aldosterone system increased with increasing doses,and the difference was still observed as time progressed. Conclusions AngiotensinⅡ-aldosterone system has an important pathophysiological function in the progression of RILI.