Objeetive ： To evaluate the role of amiodarone in preventing atrial fibrillation after coronary artery bypass grafting （CABG）. Methods： Totally 184 patients receiving CABG under cardiopulmonary bypass （CPB） were randomly divided into amiodarone group （n= 94） and placebo group （n= 90）, and patients in each group were further divided into ≥ 60 years and 60 years subgroups. Patients in amiodarone group received routine drugs ＋ amiodarone and those in placebo group received routine drugs ＋ placebo. Results： The overall incidence of postoperative AF （paroxysmal and persistent） was significantly higher in the placebo group compared with the amiodarone group （32.20% vs 6.4%, P〈0.01, OR=7.0）. The incidences of postoperative AF were similar in patients aged 〈60 years between the placebo group and the amiodarone group, but were significantly different in patients aged ≥ 60 （P〈0. 05 or P〈0.01）. The postoperative AF incidence was significantly different between 2 age subgroups （P〈0. 05 or P〈0.01） in the placebo group, but not in amiodarone group. Conclusion： Amiodarone can effectively prevent post-operative AF, especially for patients aged ≥ 60 years. Amiodarone should be recommended to patients re- ceiving CABG who aged ≥ 60 years