Aim To analyze factors that affected the coronary stent image quality of 64-slice spiral computed tomograghy. Methods 116 patients who received 64-slice spiral computed tomograghy after coronary drug-eluting metal stent implantation from 2007 to 2010 were selected.Those stents image were assessed by semi-quantitive method.Whether stent diameter,stent length,stent material,stent number and calcification status affected the stent image quality were analyzed. Results The sensitivity,specificity,positive predictive value,negative predictive value of 64-slice spiral computed tomograghy to detect significant in-stent restenosis were 85.7%,90.2%,60.0%,97.4%,respectively.Image quality of stents with diameters of >2.75 mm was better than stents with diameter of < or =2.75 mm(P><0.001).Image quality of stents which located on noncalcified plaque were better than stents which located on calcified plaque(P><0.05).Stent length,stent material,stent number did not affect the stent image quality of computed tomograghy. Conclusion 64-slice spiral computed tomograghy had ability to assess the cornary stent after implantation.64-slice spiral computed tomograghy was more suitable for assessing stents with diameters of > 2.75 mm and stents which located on noncalcified plaque.