Abstract: Objective To study the effect of metoprolol on neuroendocrine system of rabbits with diastolic heart failure. Methods Thirty New-Zealand rabbits were randomly assigned to operation group with constriction of abdominal aorta 1cm just above the right renal artery,treatment group receiving metoprolol from the first day after operation,and sham operation group serving as a control group.Changes in clinical manifestations of heart failure were carefully observed.Cardiac structure and function were investigated by regular echocardiography.Systematic and cardiac levels of local AngⅡ,ET-1,NE,and NT-proBNP were measured. Results The incidence of heart failure was obviously lower in treatment group than in operation group.The structure and function of heart were markedly improved.The serum levels of AngⅡ,ET-1,NE and NT-proBNP both in serum and myocardium were significantly lower in treatment group than in control group（25.57 vs 38.16,21.14 vs 35.96,97.90 vs 128.51,P＜0.01;11.77 vs 17.28,221.92 vs 305.76,24.33 vs 30.53,P＜0.05）. Conclusion Metoprolol can effectively inhibit the activation of neuroendocrine system of rabbits with diastolic heart failure.