Abstract: Objective: Analyze and summarize the MSCT imaging features of atypical aortic dissection, to evaluate MSCT's clinical diagnosis value to the disease. Methods: Retrospectively analyses the MSCT plain scans and CAT signs of 13 AAD cases, diagnosed by referring to the Stanford types. Results: Stanford type A: 3 cases, type B: 10 cases. Their aortic walls showed the meniscus or annular incrassation and plain scans showed high density and increase with no enhancement and 5 cases of inward moving of the calcified inner wall. Including 2 cases of intima leakage, 9 cases of atherosclerosis; 1 case of pericardial effusion, 4 cases of pleural effusion. Conclusion: CT imaging manifestations of AAD have characteristic feature: aortic walls showed the meniscus or annular incrassation, with inward moving of the calcified inner wall, intima leakage, penetrating ulcer, the structure change of aorta, atherosclerosis and so on, which erupt simultaneously pericardial effusion and pleural effusion. The advantage of AAD to scan and diagnose before and after the enhancement is obvious, plain scans combining clinic could strongly suggests that AAD, CTA are of diagnostic values.