Type 2 diabetes mellitus is a well-established risk factor for coronary heart disease and atherosclerotic change in coronary artery. So we designed a prospective randomized multi-center trial named the pioglitazone could reduce the recurrence of myocardial infarction in patients with DM and myocardial infarction(PPAR study) to evaluate whether pioglitazone could reduce the recurrence of myocardial infarction in patients with DM(HbA1c<6.5%) and myocardial infarction.