OBJECTIVE：To study the effects of methylprednisolone sodium succinate on oxidative stress and anti-endothelial cell antibody （AECA）of autoimmune emphysema model rats. METHODS ：Male SD rats were randomly divided into control group，model group and intervention group ，with 8 rats in each group. Except that control group was given same volume of complete Freund ’s adjuvant intraperitoneally ，model group and intervention group were given the mixture of human umbilical vein endothelial cells and complete Freund ’s adjuvant intraperitoneally to establish the model of autoimmune emphysema. On 2nd day after modeling ，intervention group was intraperitoneally injected with 10 mg/（kg·d）methylprednisolone sodium succinate. Control group and model group were intraperitoneally injected the same volume of normal saline ，once a day ，for consecutive 21 days. After last medication ，the right lung tissue of rats were taken for paraffin section and HE staining in each group ，and the pathological changes of lung tissue were observed. The mean alveolar number （MAN）and mean linear intercept （MLI）were measured. The contents of MDA and GSH ，the activities of SOD and glutathione peroxidase （GSH-Px）in bronchial alveolar lavage fluid（BALF）of left lung were determined ；the contents of AECA in BALF and serum were also determined. The correlation of AECA with MDA ，GSH，SOD and GSH-Px were determined in model group by Pearson analysis. RESULTS ：Compared with control group ，the pathological changes of pulmonary emphysema were obvious in model group ，MAN decreased significantly ，and MLI prolonged significantly （P＜0.01）； GSH content ， GSH-Px and SOD activities in BALF were decreased 1100，1195） significantly，the contents of AECA in BALF and serum were increased significantly （P＜0.01）. Compared with modelgroup，the pathological changes of pulmonary emphysema was improved significantly in the intervention group ， increased significantly ，while MLI shortened significantly （P＜ ·1208；GSH content ，SOD and GSH-Px activities were increased significantly，while the contents of AECA in BALF and serum were decreased significantly （P＜0.01）. AECA in BALF of rats in model group was positively correlated with MDA （r＝0.710， P＜0.05），and the AECA were negatively correlated with GSH ，SOD and GSH-Px （r＝－0.754，－0.781，－0.736，P＜0.05）. CONCLUSIONS：Methylprednisolone sodium succinate may achieve the purpose of the prevention of autoimmune emphysema through reducing oxidative stress and inhibiting the expression of AECA.