Objective To investigate the feasibility of lower extremity CT angiography with extreme low radiation dose by using iterative model reconstruction (IMR) algorithm. Methods Lower extremity CT angiography scans were acquired using a 256-slice MSCT for 60 patients: 30 patients were scanned with routine dose (RD) protocol, 120kVp, automatic tube current modulation (ACTM) with image quality index of 12 (DoseRight, Philips Healthcare), and the other 30 patients were scanned with low dose (LD) protocol, 80 kVp, 20 mAs. Images from RD-group and LD-group were reconstructed with filtered back projection (FBP) and IMR algorithms respectively. CT attenuation, image noise, SNR and CNR of 5 positions including aortic bifurcation, iliac bifurcation, proximal femoral artery, middle femoral artery, proximal popliteal artery were calculated. Subjective image quality (intravascular contrast, noise, artifacts, and diagnostic confidence) of aortoiliac, femoropopliteal and lower leg segments were assessed by two radiologists using a 4-point scale. Results Radiation dose was reduced 91.0% in LD-group compared RD-group (0.16mSv±0.01, 1.86mSv±0.51, t=-18.229, P<0.05). Higher mean intravascular attenuation, SNR and CNR as well as lower image noise were obtained in LD-group compared to RD-group (all, P<0.05). Higher subjective image quality scores were observed in LD-group compared to RD-group (P<0.05), except intravascular contrast and diagnostic confidence of aortoiliac segment. Conclusion By using of IMR, lower extremity CTA allows for a radiation dose reduction up to 91.40% meanwhile without compromising image quality.