Objective To explore the diagnostic value of CT angiography (CTA) and transcranial Doppler ultrasound (TCD) for carotid stenosis in patients with ischemic stroke. Methods A total of 84 patients with carotid stenosis diagnosed by DSA in the hospital during the period of April 2016 to April 2018 were selected. All patients underwent TCD and CTA. Pearson correlation coefficient analysis was performed to analyze the correlation among TCD, CTA and DSA in evaluating the degree of carotid stenosis. Take DSA as the golden standard, the diagnostic efficiency of TCD and CTA for carotid artery stenosis exceeding 70% was analyzed. Results The degree of carotid stenosis diagnosed by TCD and CTA was (65.32±21.18)% and (63.48±20.89)% respectively, which was positively correlated with the result of DSA (63.11±19.62)% (r=0.913, 0.986, P<0.05). The sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Kappa value of CTA in the diagnosis of carotid stenosis in patients with ischemic stroke were 93.75%, 96.39%, 95.24%, 95.24 %, 95.24% and 0.903, which were significantly higher than that of TCD(81.25%, 84.34%, 82.99%, 78.79%, 85.37% and 0.704) (P<0.05). Conclusion CTA is superior to TCD in the diagnosis of carotid stenosis in patients with ischemic stroke, and is expected to become an alternative to replace DSA.