〔Abstract〕 Objective To evaluate the clinical value of combining low-dose energy spectrum CT with virtual un-enhanced(VUE) scanning and deep-learning image reconstruction(DLIR) in aortic CT angiography(CTA). Methods In a prospective study, 94 patients scheduled for aortic CTA were randomized into two groups: a low-dose energy spectrum group and a standard 100 kVp enhancement group, with 47 patients in each. All patients initially underwent a true un-enhanced(TUE) scan at 120 kVp using adaptive statistical iterative reconstruction-V(ASIR-V) at 40% for image reconstruction. The low-dose group received enhanced scans using gemstone spectral imaging(GSI) mode with DLIR-H, producing 60 keV virtual monoenergetic images(VMIs) and VUE images. The standard group was scanned at 100 kVp, with images reconstructed using ASIR-V at 50%. Parameters were measured including CT values, noise(SD), signal-to-noise ratio(SNR), and contrast-to-noise ratio(CNR) for key vascular and muscular areas, alongside the effective radiation dose(ED). Two radiologists evaluated the image quality using a 5-point scale. Results The low-dose group exhibited significantly higher SNR and CNR values in the ascending aorta, descending aorta, abdominal aorta, and common iliac artery compared to the standard group(P<0.05), with comparable subjective quality scores. The VUE images also demonstrated superior SNR values in the abdominal aorta, common iliac artery, and psoas major muscle, and CNR value in the ascending aorta compared to TUE images, with similar subjective quality. Importantly, the ED in the low-dose group was about 40% lower than that of the standard group. Conclusion Low-dose energy spectrum CT with DLIR in aortic CTA can significantly enhance SNR and CNR, while approximating the image quality of traditional TUE scans, thereby substantially reducing radiation exposure.