Abstract： Objective To investigate the impact of simvastatin on blood lipid and the incidence of atrial fibrillation and ischemic-related events in patients with acute myocardial infarction accompanied by paroxysmal atrial fibrillation. Methods One hundred and three patients with acute myocardial infarction and paroxysmal atrial fibrillation were selected as subjects, and were divided into a simvastatin group and a control group. Forty-five patients were in the simvastatin group, who took simvastatin 20mg/d orally for 18 months; fifty-eight patients were in the control group, and received conventional therapy except for statins. All patients were followed up for 18months. The level of blood lipid, recurrence rate of paroxysmal atrial fibrillation, incidence rate of persistent or permanent atrial lipids did not change significantly in the control group (P＞0.05); concentrations of total cholesterol (TC) and low density lipoprotein five patients during 18 months follow-up in the simvastatin group (11.1%), whereas it occurred in 14 patients of the control group(24.1%, P＜0.05); the occurrence rate of persistent or permanent atrial fibrillation in the simvastatin group was 4.4%, which was lower than (6.6%), two rehospitalizations for deterioration of coronary heart diseases (4.4%), three cardiac deaths (6.6%), and one cerebral stroke (2.2%), which was lower evidently than in the control group (41.4%, P＜0.05). Conclusions Simvastatin can not only decrease the levels of serum TC and LDL-C but also prevent the occurrence of atrial fibrillation and ischemic-related events.