PurposeTo observe the effects of blocking the renin-Angiotensin-Aldosterone system at different sites in experimental congestive heart failure (CHF)rats. Methods Six weeks after coronary ligation, rats( n = 66)were randomized to benalapril, losartan, spironolactone, placebo, and treated for 6 weeks. Sham-operated rats( n = 18) served as controls. Six weeks later left ventricular hemodynamics were measured. Results In the hemodynamic variables, HR was not significantly different between groups. Compared four treatment groups with sham-operated group, LVEDP increased, LVPSP and ± dp/dtmax decreased (P＜0.05). Compared with placebo group,all data in spironolactone group were not significantly different, LVEDP, mortality in benalapril group and in losartan group decreased, LVPSP and ± dp/dtmax in benalapril group and in losartan group increased(P ＜ 0.05). ConclusionsAdministration of ACEI and Ag Ⅱ-AT1 antagonist are effective in preventing from cardiac function deterioration, while spironolactone treatments are not. Spironolactone has tendency in decreasing LVEDP.