Abstract: Objective: To study the roles of brain natriuretic peptide(BNP) in diagnosis and prognostic evaluation of patients with acute coronary syndrome(ACS). Methods: The levels of BNP were detected in 54 patients with acute myocardial infarction(AMI), 35 patients with unstable angina pectoris(UAP),20 patients with stable angina pectoris(SAP) and 20 healthy volunteers as controls. The correlations were compared between the number of impaired coronary arteries,the lesions of left main coronary artery,the Gensini scores of coronary artery and the levels of BNP respectively. The mortality of the patients with ACS in hospital at 30 days and 3 months, and the major adverse cardiac events(MACE),cardiogenic death, re-myocardial infarction, recurrent angina,consequential heart failure and the composite endpoint rates of readmission were analyzed. Results: The levels of BNP in group AMI and group UAP were significantly higher than those in group SAP and controls(P < 0.01),and the level of BNP in group AMI was significantly higher than it in group UAP(P < 0.01). Multivariate logistic regression analysis showed that,the level of plasma BNP was independent with the risk factors of coronary heart disease,such as age,gender,family history,smoking, hyperlipidemia,high blood pressure,diabetes,and so on, but it was associated with mortality and rates MACE(P < 0.05-P < 0.01). Conclusions: The levels of BNP in patients with ACS increase significantly and are associated with degrees of coronary artery disease and myocardial ischemia. The change of plasma BNP is an independent predictor for mortality and incidence of MACE in hospital at 30 days and 3 months among ACS patients.