Aim To observe the levels of plasma B-type natriuretic peptide（BNP)in people of non-hypertension（non-HP)and patients of isolated systolic hypertension（ISH)with or without left ventricular hypertrophy（LVH)and the changes of BNP, LVH and diastolic function before and after administration of angiotensin receptor blocker（ARB）, and to investigate the associations between the changes of BNP and LVH or diastolic function. Methods Thirty-three were designed to non-HP group, thirty-eight patients with ISH, and forty-two patients with ISH and LVH served as HP groups. Echocardiography was performed to determine left ventricular mass index(LVMI)and E/A ratio, and radioimmunoassay was used to detect plasma BNP levels. Results Plasma BNP was significantly higher in two ISH groups than that in non-HP group（P<0.05 or P<0.01）. LVMI was significantly increased（P<0.05)while E/A ratio reduced（P<0.01)in patients of ISH with LVH compared with those without LVH. After administration of ARB-valsartan, BNP levels lowered in HP groups(P<0.05 or P<0.01）, and LVMI reduced while E/A ratio increased in patients of ISH with LVH（P<0.01）. The BNP levels correlated positively with LVMI（r²0.61, P<0.01)and negatively with E/A ratio（r²0.26, P<0.01)before treatment. Conclusion The plasma BNP may be a sensitive biomarker for reverse remodeling in LVH and improvement in diastolic dysfunction.