Objective To assess the value of CT angiography (CTA) in diagnosis of re-entry tears in type B aortic dissection. Methods One hundred and ten patients with typical type B aortic dissection were enrolled. Data derived from the CTA scans of all the patients and DSA of 70 patients were reviewed. The number, location and size of the re-entry tears were calculated and analyzed. CTA findings were compared with DSA results by using Kappa statistics. Results The mean number of re-entry tears was 3.41±1.90, and 83.64% (92/110) patients had multiple tears. Re-entry tears occurred in the middle of the abdominal aorta were more common than that in the other palce of aorta. The large ones commonly located in the most remote position of dissection. The sensitivity and specificity of finding re-entry tears with CTA was 93.78% and 88.89% respectively, the Kappa value was 0.827 (P＜0.01). Conclusion The consistency between CTA and DSA was good. The re-entry tears in type B aortic dissection can be depicted clearly with CTA, and CTA can be used as the main method for further observation and follow-up of this disease.