Objective To assess the image quality and the feasibility of double-low dose (80 kv and 30 mL contrast medium) combined with iterative reconstruction (IR) in whole aortic CT angiography. Methods Sixty post-operative patients were prospectively enrolled in this study and randomly separate into two groups with a routine dose CTA protocol (FLASH, reference parameters 120 kv, 60 mL contrast medium, RD) and a low dose CTA protocol (FLASH, reference parameters 80 kv, 30 mL contrast medium, LD), respectively. Images were reconstructed using filtered back projection (FBP) for RD dataset and using IR for LD dataset. Two radiologist reviewed the image quality using a 5-point scale (1 = non-diagnostic, 5 = excellent), measured objective image noise and calculated the signal to noise ratio (SNR), contrast to noise ratio (CNR). The radiation dose was recorded. Results The subjective image quality and CNR was no significantly statistical difference in LD, compared with RD ( all p > 0.05), but image noise and SNR was decreased in part of aortic segment. Compared with RD, the effective radiation dose and contrast medium volume in LD decreased by 72% and 50%, respectively (2.12 ± 0.15 mSv vs. 7.47 ± 0.54 mSv, 30 mL vs. 60 mL, all p < 0.05). Conclusion 30 mL contrast medium at 80kV for aorta CT angiography significantly reduces radiation and contrast agent volume while maintaining the diagnostically image quality.