Objective：To evaluate the clinical effect of three - dimensional（3D）reconstruction images of coronary CT angiography （CCTA）in preoperative planning of off-pump coronary artery bypass grafting（OPCABG）. Methods：The clinical data of 158 patients who underwent OPCABG from January 2021 to March 2023 in the department of cardiovascular surgery of the First Affiliated Hospital of Nanjing Medical University were retrospectively analyzed. Among them，113 patients underwent OPCABG guided by coronary angiography（CAG）（conventional group）. On the basis of CAG，CCTA and 3D reconstruction of images were completed in 45 cases to assist OPCABG（3D group），and the operation was guided by comprehensive analysis of the results of the two imaging examinations. The outcome measures included operation time，intraoperative blood loss，ventilator usage time，postoperative monitoring period and hospital stay，postoperative atrial fibrillation，acute kidney injury，secondary tracheal intubation，cerebral infarction，cardiovascular adverse events and other complications，and 1 year postoperative cardiac ultrasound and CCTA follow-up results. Results：There was no significant difference between the two groups in the ventilator usage time，the postoperative monitoring period，the time of hospital stay，and the results of CCTA and cardiac ultrasound follow-up 1 year after surgery（P ＞ 0.05）. However，the operation time of the 3D group was（250.7 ± 41.4）min and the conventional group was（271.0 ± 57.2）min，and the differences between the two groups were statistically significant（P ＜ 0.05）. Moreover，the amount of blood loss during the 3D group was less than that of the conventional group （P < 0.05）. Conclusion：Compared with conventional CAG guided OPCABG，the addition of CCTA can shorten the operation time， reduce the amount of intraoperative blood loss，and obtain better surgical results.