Objective：To explore the influence of preoperative left ventricular ejection fraction（LVEF）on the risk of atrial fibrillation（AF）recurrence after combined Cox Maze Ⅳ and valvular surgery. Methods：We retrospectively reviewed clinical and follow up data of patients who underwent Cox Maze Ⅳ combined with valvular surgery at the Department of Cardiothoracic and Vascular Surgery，the First Affiliated Hospital of Nanjing Medical University，between January 2014 and December 2023. Patients were classified by echocardiographic LVEF measured within one week before surgery into a low LVEF group（LVEF＜50%）and a normal LVEF group（LVEF≥50%）. Propensity score matching（PSM）was performed at a 1∶2 ratio to balance baseline covariates between groups. Postoperative AF recurrence rates were compared between matched groups. Results：A total of 513 patients were initially included. Before matching，the low LVEF group comprised 66 patients（39 males，27 females）with a mean age of（59.7±8.7） years，while the normal LVEF group comprised 447 patients（179 males，268 females）with a mean age of（59.4±9.5）years. After PSM， 64 patients remained in the low LVEF group and 125 in the normal LVEF group. The postoperative AF recurrence rate was significantly higher in the low LVEF group compared to the normal LVEF group（log-rank，P=0.013）. Cox regression analysis identified low LVEF as an independent risk factor for AF recurrence after Cox - Maze Ⅳ combined with valvular surgery. Conclusion：Lower preoperative LVEF is associated with a higher risk of AF recurrence after combined Cox Maze Ⅳ and valvular surgery.