Objective:To investigate the antioxiative effects of spironolactone ,an aldosterone receptor blockade,on kidney of rats with unilateral ureteral obstruction(UUO). Methods:Thirty wistar rats underwent UUO and then received vehicle(n = 11) or spironolactone(50mg·kg-1·d-1 by daily gastric gavage,n = 12) during the 15 days from the day before surgery. Additional 7 rats were sham operated. All the rats were killed at 14 days after surgery. Histological changes were observed by HE and Masson staining. Malondialdehyde(MDA),superoxide dismutase(SOD) as well as aldosterone(ALD) content were measured. Results:UUO induced a significant increase in MDA and ALD content but a marked decrease in SOD content and severe morphology changes. However,spironolactone ameliorated what had mentioned. Conclusions:Spironolactone can suppress oxidative stress and alleviate renal in rats with UUO by reducing lipid peroxidation production and improving antioxidative enzyme contents.