Abstract: Objective To observe the effect of diosmin on oxidative stress and renal function in rats after ischemia/reperfusion（I/R） injury. Methods One hundred and eighty SD rats were randomly divided into sham operation（SO） group,I/R injury model group,and diosmin +I/R injury group.Serum levels of malonaldehyde（MDA）,superoxide dismutase（SOD）,creatinine（Scr）,and blood urea nitrogen（BUN） in their kidney tissue were measured by ELISA. Results The serum MDA level increased gradually in kidney tissue of rats at 1,3,6 and 12h after I/R injury and reached its peak at 12h,and was significantly higher in I/R injury model group and diosmin +I/R injury group than in sham operation group（P＜0.01）.Then,the serum MDA level decreased gradually and was significantly lower in diosmin+I/R injury group than in I/R injury group（P＜0.01）.The SOD activity decreased significantly in renal tissue of rats,reached its maximum at 24 after I/R injury,then began to increase,and was significantly higher in diosmin +I/R group than in I/R injury group at 6,12,24 and 48h after I/R injury（P＜0.01 or P＜0.05）.However,no significant difference was found in SOD activity between diosmin +I/R injury group and sham operation group.The serum Scr and BUN levels were significantly lower in diosmin +I/R injury group than in I/R injury group after I/R injury（P＜0.01 or P＜0.05）. Conclusion I/R can increase lipid peroxidation in renal tissue of rats.Diosmin can protect renal function by reducing its anti-free radical injury and alleviating its lipid peroxidation.