Objective: To study the relationship between preoperative plasma interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), homocysteine (Hcy), endothelin-1 (ET-1) levels and new-onset atrial fibrillation (AF) after coronary artery bypass grafting (CABG). Methods: In the study, 148 patients who underwent isolated CABG in Peking University People’s Hospital from January 1, 2017 to December 30, 2017 were enrolled, of whom 39 had new-onset AF. The fasting venous blood was collected within 24 hours before the surgery. The preoperative plasma IL-1, IL-6, TNF-α, Hcy, ET-1 levels were detected by enzyme-linked immunosorbent assay (ELISA). The patients were divided into AF group and non-AF group according to whether new-onset AF occurred after operation. After 1 ∶1 propensity score matching (PSM), 38 people were in each group. The paired sample t-tests were performed on the five factors’ concentrations of the matched AF group and the non-AF group respectively. If the concentration values did not conform to the normal distribution, the Wilcoxon signed rank sum test was performed. Conditional Logistic regression analysis was performed on the concentrations of the five indicators to explore the correlation between preoperative plasma concentrations of IL-1, IL-6, TNF-α, Hcy, ET-1 and postoperative new-onset AF after CABG. Results: After a 1 ∶1 propensity score matching, the AF group was comparable to the non-AF group. The concentrations of IL-1, IL-6, TNF-α, and Hcy in the AF group were higher than those in the non-AF group [(0.867±0.589) ng/L vs. (0.742±0.262) ng/L, 21.55 (6.50, 209.90) ng/L vs. 17.95 (3.60, 86.70) ng/L, 20.30 (5.70, 361.00) ng/L vs. 21.50 (7.50, 251.80) ng/L, (0.29±0.11) μmol/L vs. (0.27±0.09) μmol/L], but the differences were not statistically significant (P=0.165, P=0.891, P=0.817, P=0.285). After the conditional Logistic regression analysis, the above four variables were not predictors of new-onset AF after CABG. The concentrations of ET-1 in the matched AF group and non-AF group were (25.80±6.20) ng/L and (29.10±8.54) ng/L, respectively. The correlation between preoperative low plasma ET-1 concentration and the new-onset AF after CABG were statistically significant (P=0.003). After conditional Logistic regression analysis, preoperative plasma ET-1 concentration was correlated with postoperative new-onset AF after CABG (P=0.039, adjusted OR=0.637, 95%CI: 0.415-0.977). Conclusion: The levels of preoperative plasma IL-1, IL-6, TNF-α and Hcy in the patients with new-onset AF after CABG were higher than those in the patients without AF, but the difference was not statistically significant. Preoperative plasma low ET-1 concentration was statistically associated with new-onset AF after CABG.