Objective To explore the clinical application of the dose of low-voltage and low-iodine contrast agents in head and neck CT angiography (CTA). Methods By the random number table method, 80 patients undergoing head and neck CTA were divided into routine group and double-low group, with 40 cases in each group. The contrast agent dose of CTA and the tube voltage in routine group were 60 mL and 120 kVp, respectively. Those in the double-low group were 0.3 ml/kg and 100 kVp, respectively. The dose of contrast agents used and dose-length product (DLP) in both groups were recorded, and the size-specific dose estimate (SSDE) was calculated. Images of both groups were evaluated objectively and subjectively. Results The dose of contrast agents, DLP and SSDE in the double-low group were significantly lower than those in the routine group (P<0.05). The objective image quality scores in the left and right middle cerebral arteries of the double-low group were significantly lower than those in the routine group (P<0.05). However, there was no significant difference in image quality score in other interest areas between groups (P>0.05). There was no significant difference in subjective evaluation and passing rate of CTA image quality between the two groups (P>0.05). Conclusion Lowvoltage and low-iodine contrast agent doses can significantly reduce the scanning radiation dose of head and neck CTA and the amount of contrast iodine. The image quality can meet the clinical diagnosis.