To determine the clinical value of 64-slice computed tomography angiography (CTA) in the evaluation of vessel before and after coronary artery bypass graft (CABG) surgery, we retrospectively collected the coronary artery imaging data of 46 patients undergoing 64 slice CT before CABG surgery in the period from July 2006 to May 2007, and we evaluated 14 patients with 39 coronary grafts in the same period to determine the diagnostic accuracy of CTA before and after CABG surgery. In 46 patients, 64-slice CT enabled the visualization of the entire coronary tree with diagnostic image quality. Sensitivity, specificity, and accuracy for the detection of stenosis > or = 50% were 92.11%, 95.64%, 94.97%, respectively. In 14 patients with 39 coronary grafts, 35 (35/39, 89.74%) bypass grafts were found to be of no stenosis; low degree of restenosis was found in 4 (4/39, 10.26%) bypass grafts, and no graft was found to have high degree of restenosis. So we concluded that, with the use of 64-slice CTA, we can accurately evaluate the degree of stenosis of vessel before and after CABG surgery.