Objective To evaluate the protective effect of captopril(CAP) on acute renal ischemia-reperfusion injury in rabbits. Methods Model of acute renal ischemia-reperfusion injury was induced with the right suprarenal abdominal aorta being occlused for 30min then unclamped for 180 min. 24 rabbits were randomly divided into false operating group (A, n = 8), ischemia-reperfusion group (B, n = 8), and CAP-group (C, n = 8). In group C, CAP 2mg.kg~(-1) was given intravenously 5min prior to clamping and infused at a rate of 0.5mg. kg(-1). h(-1) for 15min. Other groups of rabbits received normal saline as controls,but the abdominal aorta was not occlused in group A. The parameters, including BUN, Cr, SOD, MDA, AT-Ⅱ and β_2-MG, were observed before, during ischemia and after reperfusion. The kidney specimens were examined using light and electron microscopy' Results In group C renal cortex and serum MDA,AT-Ⅱ concentration after reperfusion were significantly decreased (P＜0.01),SOD activity increased significantly (P<0.01) and serum BUN,Cr,urine β_2-MG levels decreased markedly compared with those in group B (P<0. 05 or P<0.01 )' The Paller's score for acute renal tubular injury was evidently lower in group C than that of group B (25. 00±7. 56 vs 82. 50±16. 69,P<0.05)' Under electron microscopy,renal pathology associated with acute tubular injury and necrosis were observed in group B, meanwhile, it was obviously alleviated in group C' Conclusion Captopril can effectively protect rabbit kidneys against ischemia-reperfusion injury during suprarenal abdominal aortic crossclaming.