Objective: To investigate the incidence and relative risk factors of post coronary artery bypass grafting(post-CABG) atrial fibrillation(AF). Methods: 312 patients with CABG were reviewed and divided into an AF group and a non-AF group. Statistical analysis was used to compare the data between the two groups and screen for risk factors of post-CABG AF. Results: 103/312 (33.01%) patients developed post-CABG AF. Univariate analysis showed that patients in AF group compared with those in non-AF group were more likely to have advanced age (≥70 years), early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement (≥40 mm), a history of AF, prolonged p-wave duration (≥120 ms) and increased number of grafts (≥3). Multivariate logistic regression analysis showed that advanced age (≥70 years), early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement (≥40 mm) and a history of AF were highly related to post-CABG AF. Conclusion: The incidence of AF in patients following CABG was 33.01% in this study. Advanced age, early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement and a history of AF were independent risk factors of post-CABG AF.