Objective To study the diagnostic value of 64-slice CT in type DeBakey I - III aortic dissection. Methods 40 cases of patients with aortic dissection confirmed by pathology or DSA admitted into the hospital from February 2013 to February 2015 were selected as the research object and all received 64-slice CT scan. The image data was processed by 3D reconstruction and the CT imaging features were analyzed. Results There were 10 cases (25%) of type I, 3 cases (7.5%) of type II and 27 cases (67.5%) of type III. True lumen was mainly circular, accounting for 75.0% while false lumen mainly was crescent shaped, accounting for 75.0%. Intimal tears located in the proximal descending aorta accounted for 42.5%, in ascending aorta for 32.5% and 10% without show. CT scan: there was 4 cases of false lumen of high density and 7 cases of intimal calcification calcified plaque ingression; enhanced scanning: there were 17 cases of true and false lumen in arterial phase significantly enhanced and the enhancement degree of true lumen was of 19 cases greater than that of the false lumen; In venous phase, the density of false lumen was of34 cases greater than that of the true lumen. There were 2 cases of rue and false lumen with the same density; In addition, there were 4 cases of false lumen without enhancement or small pieces with enhancement. Conclusion 64-slice spiral CT is of important diagnostic value in aortic dissection DeBakey typing, identification of true and false cavity and crevasse display. It is worth further application in the clinical diagnosis of aortic dissection.