Abstract： Objective To evaluate graft patency at one year after coronary artery bypass grafting （CABG） and analyze the risk factors of graft occlusion. Methods We prospectively included 71 consecutive patients with coronary heart disease who underwent CABG in First Affiliated Hospital of Harbin Medical University from June to December 2010. There were 37 males and 34 females with their average age of 59.8±7.7 years. All the patients underwent CABG performed by the same surgeon， and received standard drug therapy after surgery. At 1 year after CABG， 256-slice multislice computed tomography （MSCT） angiography was performed to evaluate graft patency. All the patients were divided into two groups according to their graft patency during follow-up， including 16 patients in the occluded graft group and 55 patients in patent graft group. Preoperative， intra-operative and postoperative variables were collected. Univiariate analysis and logistic regress analysis were performed to analyze risk factors of graft occlusion. Results The graft patency was 91.0% （172/189） at 1 year after CABG. Univiariate analysis showed that pre-operative cholesterol （t=-2.389，P=0.017）， diffused coronary artery disease （χ2=4.449，P=0.042）， diameter of target vessels （t=5.064，P=0.000）， non-adherence to prescribed antiplatelet medications （χ2=10.175，P=0.008） were potential risk factors of graft occlusion after CABG. Logistic regress analysis showed that diameter of target vessels ［RR=0.014，95% CI （0.001，0.229），P=0.003］ and non-adherence to prescribed antiplatelet medications ［RR=13.375，95% CI （1.075，175.536），P=0.044］ were significant risk factors for graft occlusion. Conclusion The graft patency is satisfactory at 1 year after CABG. Graft patency after CABG is closely related to the stenosis degree of target vessels and adherence to prescribed antiplatelet medications after surgery.