This study is designed to evaluate the efficacy and safety of Recombinant Human Brain Natriuretic Peptide (rhBNP) in improving ventricular remodeling and cardiac function after acute anterior myocardial infarction undergoing percutaneous coronary intervention. 100 patients with acute anterior myocardial infarction after primary Percutaneous Coronary Intervention (pPCI) are randomly assigned 1:1 to rhBNP group(n=50) and control group(n=50) with follow-up of 24 weeks. Both groups are treated with standard therapy of AAMI, with the rhBNP group intravenous dripping rhBNP after pPCI for 3 days and the control group treated with placebo at the same time. The primary endpoint is the change in N terminal pro-B-type natriuretic peptide（NT-proBNP ）and cardiac troponin T(cTnT) level.The secondary endpoint is the change in 24-week echocardiographic including left ventricle ejection fraction (LVEF) , left ventricular end-diastolic volume index (LVEDVI) and left ventricular end-systolic volume index (LVESVI), arrhythmia and cardiovascular events (death, cardiac arrest or cardiopulmonary resuscitation, hospitalization due to heart failure or angina pectoris).