Objective To evaluate the value of spiral CT postprocessing volume reconstruction (VR) in thoracic aortic aneurysm. Methods Select 43 cases of thoracic aortic aneurysm treated in our hospital from January 2015 to November-2016, patients were examined by multi-slice spiral CT, and collect the clinical data and imaging data of 43 cases, to observe the multi-slice spiral CT scan and VR images, compare the detection rate of two kinds of examinations for thoracic aortic aneurysm, and analyze its application value. Results The detection rate of CT scan in thoracic aortic aneurysm was 79.06% (34/43), the detection rate of VR in thoracic aortic aneurysm was 100% (43/43), and the detection rate of CT scan for thoracic aortic aneurysm was lower than VR, the difference was statistically significant (χ2 =8.009, P<0.05). In 43 patients, thoracic aortic aneurysms were characterized by cystic or spindle shaped bulging of the aorta during CT scan, local thickening or abnormal morphology of the aorta, a small number of patients with pleural effusion, 55.81% (24/43) patients with marginal calcification of the arc, tumors in ascending aorta are >4 cm in diameter and (4.51±0.57)cm in diameter, the average diameter of tumor in descending aorta was (3.01+0.35) cm. After CT enhancement, the images were mainly light to moderate enhancement of the tumor, and the local protrusion was filled with contrast medium. VR can visually display the local protuberance on the aortic arch, the tumor and normal aorta obviously different, clearly show that the tumor morphology based on MIP and MPR images, clearly and accurately display the vessel shape, the overall shape of the aorta. Conclusion The volume and reconstruction of spiral CT can display the location and shape of thoracic aortic aneurysm in an intuitive and three-dimensional manner, with high detection rate. It can be used as an operation plan for clinical and improve reliable imaging data.