Aim To observe the expression of angiotensin Ⅱ(AngⅡ) and plasminogen activator inhibitor-1(PAI-1) in rabbits atherosclerotic plaques,and to study the inhibiting efficiency of captopril and valsartan. Methods Male New Zealand white rabbits were randomly divided into four groups: cholesterol group,captopril group,valsartan group and control group.After feeding 10 weeks,plasma PAI-1 activity was evaluated by spectrphotometric assy,plasma AngⅡ level was measured with competitive radioimmunoassays.The expression of AngⅡ and PAI-1 in atherosclerotic plaques were observed by immunohistochenistry measure. Results In cholesterol group,plasma AngⅡ level and plasma PAI-1 activity were increased significantly compared with control group(p<0.01),and the percent of positive cells of AngⅡ and PAI-1 in atherosclerotic plaques were higher compared with control group(46.97%±14.32% vs 4.17%±1.01% and 48.5%±13.46% vs 1.33%±0.52% respectively,p<0.01).Captopril and valsartan significantly reduced plasma AngⅡ level and PAI-1 activity compared with cholesterol group(p<0.05).Also captopril and valsartan markedly decreased the percent of AngⅡ positive and PAI-1 positive cells in atherosclerotic plaques compared with cholesterol group(26.30%±5.00% vs 46.97%±14.32% and 20.37%±(8.23%) vs 48.50%±13.46%,p<0.05 in captopril group;27.83%±7.30% vs 46.97%±14.32% and 22.50%±(7.06%) vs 48.50%±13.46%,p<0.05 in valsartan group).The expression of PAI-1 were positively correlated with the expression of AngⅡ in atherosclerotic plaques(r=0.796,p<0.01). Conclusion The expression of AngⅡ and PAI-1 in atherosclerotic plaques were increased,there was significant correlation between the expression of PAI-1 and AngⅡ,both captopril and valsartan have the efficiency of inhibiting the expression of Ang Ⅱ and PAI-1 in plaques of rabbit atherosclerosis.