Aim To investigate the value of dual-source 256 slice spiral CT dual-energy scanning in diagnosis of aortic intramural hematoma （AIH）. Methods AIH CT imaging data were retrospectively reviewed from Oct 2012 to Aug 2014. 41 patients with AIH were diagnosed by dual-source 256 slice spiral CT dual-energy scanning. The original data were processed by image postprocessing technology, including virtual non-contrast （VNC）, multi-planar reconstruction （MPR）, curved planar reconstruction （CPR）, and maximum intensity projection （MIP）. Results AIH caused aortic wall thickening, and all thicken aorta walls were more than 5 mm. There were 39 cases of crescent-thicken and 2 cases of circular-thicken. The aortic wall calcified plaque could be seen in 30 cases of patients, and within-shifted calcified plaque could be seen in 25 cases of patients. There were 32 cases with ulcer niche and 3 cases with lining leakage in the aortic wall. But no intimal tear crevasse could be found in all patients. In addition, there were 8 cases with simple pleural effusion, and 2 cases with pleural effusion and pericardial effusion. Conclusions AIH can be diagnosed fast, accurately, and noninvasively by dual-source 256 slice spiral CT dual-energy scanning. Dual-source 256 slice spiral CT dual-energy scanning can provide important information for constituting clinical reasonable treatment scheme.