To investigate the predictive value of preoperative triglyceride-glucose (TyG) index on atrial fibrillation recurrence after valvular surgery with concurrent Cox-maze Ⅳ ablation. The data of the patients who underwent valvular surgery with concurrent Cox-maze Ⅳ ablation from June 2017 to May 2022 in the Department of Cardiac Surgery, Beijing Anzhen Hospital were retrospectively collected, and the patients were divided into the recurrence group and non-recurrence group. Baseline clinical data and results of laboratory tests were collected and TyG index was calculated. The univariate and multivariate Cox proportional regression analysis were used to explore the risk factors of atrial fibrillation recurrence after Cox-maze Ⅳ ablation. The value of TyG index in predicting atrial fibrillation recurrence was obtained by plotting receiver operating characteristic (ROC) curve. A total of 424 patients were in the final analysis, including 300 males and 124 females, with an average age of (58.2±13.4) years. The median follow-up time was 32.7 months (17.3-49.6 months). There were 117 and 307 patients in the recurrence and non-recurrence groups, respectively. Compared with the non-recurrence group, the TyG index in the recurrence group was higher (9.21±0.38 vs 8.34±0.72, =0.011). The multivariate Cox regression analysis showed that TyG index (=2.021, 95%: 1.374-3.245, <0.001), C-reactive protein level (=1.127, 95%: 1.007-1.535, =0.026) and mitral stenosis (=1.038, 95%: 1.004-1.483, <0.001) were risk factors for atrial fibrillation recurrence after Cox-maze Ⅳ ablation. In addition, TyG index was a predictor of atrial fibrillation recurrence according to ROC curve analysis [area under the curve (AUC)=0.847, 95%: 0.796-0.871, <0.001]. The TyG index is an effective indicator to predict the recurrence of atrial fibrillation after valvular surgery with concurrent Cox-maze Ⅳ ablation.