Objective To evaluate the efficacy of Radiofrequency （RF） modified maze procedure combined with open-heart surgery for atrial fibrillation （AF）. Methods From January 2003 to October 2004, 66 patients underwent the RF modified maze Ⅲ procedure for AF combined with open-heart surgery. The preoperative and postoperative indexes of electrocardiogram and echoeardiogram were compared through retrospective analysis and follow-up. Postoperative cardiac function and thromboembolie events were evaluated through telephone and mail. Results The time needed for RF modified maze Ⅲ was 18.61±3.56 min. There were no hospital deaths and the complications was 15.15%（10/66）. Follow-up duration was 14.25±6.47 months with 95.45%（63/66） completion. At the lastest follow-up, the rate of freedom from AF was 80.95% （51/63）and the rate of restoration to sinus rhythm was 74.60%（47/63）. No thromboembolic events was seen. 77.78%（49/63） of patients were in NYHA class Ⅰ. Significant decrease was seen in both left atrial dimension （LAD） and left ventricular dimension （LVD）（P〈0.01） more than 6 months after operation. Conclusion RF modified maze Ⅲ procedure as an adjunctive procedure is safe, time-sparing and effective in eliminating AF.