Objective To study the diagnosis of carotid artery stenosis and plaque morphology with CT angiography (CTA), color Doppler ultrasound (CDFI) and digital subtraction angiography (DSA), and DSA as the gold standard, the diagnostic accuracy of CDFI and CTA was analyzed. Methods 180 cases of patients with internal carotid artery stenosis were selected who diagnosed by DSA examination in our hospital from January 2013 to June 2015 ,and successively CDFI, CTA inspection, compare three methods of detection for the diagnosis of internal carotid artery stenosis and plaques form as a result, with DSA as the gold standard, analyze the diagnostic accuracy of CTA and of a CDFI. Results DSA diagnosis in patients with internal carotid artery type irregular patches of blood vessels, article 180 shall rule type patches of vascular article 180, article type and irregular CTA diagnosed patients with internal carotid artery plaque blood vessels, article 179 of the rules of type patches of blood vessels, article 181 of a CDFI confirmed type irregular internal carotid artery plaque in patients with vascular article 191, article article rule type plaque blood vessels 169. With DSA as the gold standard, the sensitivity of CTA and of a CDFI respectively 98.89%, 85.56%, specificity of 99.44%, 79.44% respectively, the positive predictive value were 99.44%, 80.63%, negative predictive value were 98.90%, 84.62%, the accuracy of 99.17%, 82.50% respectively. Conclusion Compared with CDFI, CT angiography (CTA) for internal carotid artery stenosis rate is more than or equal to 70%, irregular plaque diagnosis accurate rate is high, and the accuracy of the gold standard of DSA in diagnosis of with high consistency, and is easy to use, in certain circumstances can replace DSA and avoid the invasive and potentially dangerous.