Objective Mainly discusses CT scan in the diagnosis of aortic dissecting aneurysm scheme and theoretical basis for improving CT scan screening accuracy, reduce misdiagnosis and missed diagnosis. Methods Two experienced radiologists have analyzed 58 CT scan images of suspected aortic dissecting aneurysm patient, and recording the expected to CT sign which is associated with aortic dissecting aneurysm. Seven kinds of CT manifestations were included in this study, including: lumen uneven density, endometrium valve calcification of aortic diameter broadening, mediastinal hemorrhage, pericardial effusion, pleural effusion, double pneumonia disease,Finally 58 patients of 39 cases were confirmed as the main artery dissection aneurysm;This research adopts the 2 test or Fisher's Exact Test to investigate the CT signs and the correlation of aortic dissecting aneurysm, and through the ROC curve analysis to explore the diagnosis of aortic dissecting aneurysm. Results the single factor analysis showed that the lumen Uneven density(P<0.001), Move in endometrium valve calcification(P=0.002), pleural effusion(P=0.001), and there are significant correlation between aortic dissecting aneurysm.Through joint of ROC curve analysis to build the three models: the model of an "lumen uneven density" as a diagnostic basis;Model 2 with "lumen uneven density" and "membrane valve calcification within shift" as a diagnostic basis;Model 3 "lumen uneven density", "inside lining valve calcification shift" and "pleural effusion" three signs as a diagnostic basis. Conclusions Comprehensive utilization of CT scan of the seven signs is of great significance in the early diagnosis of aortic dissecting aneurysm.