Objective To study the value of coronary CT angiography in the diagnosis of restenosis after coronary stent implantation. Methods 87 cases of patients who received reexamination after coronary stent implantation from March 2014 to March 2016 were selected as the subjects, and all patients underwent coronaryangiography at 1 day to 14 days after coronary CT angiography.126 stents with good-quality imageswere selected for imaging evaluation. With the results of coronary angiography as the golden standard, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of coronary CT angiography in the diagnosis of restenosis after coronary stent implantation were calculated. Results The sensitivity, specificity, positive predictive value, negative predictive value and accuracy rate of coronary CT angiography in the diagnosis of instent restenosis were 80%, 96.9%, 88.9%, 93.9% and 92.9%, respectively. Conclusion Coronary CT angiography is a noninvasive, convenient and reliable method for the detection of coronary artery disease. It can be used to assess restenosis after coronary stent implantation, which is helpful for postoperative treatment of patients.