Abstract: Objective: We intend to explore the clinical value of double-low (low tube electrodepressed contrast agent dosage) examination technique which is based on KARL 3D iterative reconstruction when applied in bronchial artery imaging. Methods: We performed retrospective analysis on the clinical imaging data of 60 patients with hemoptysis treated in Wuhan Pulmonary Hospital from July to September 2020. 30 patients were randomly selected to use plan A while the rest 30 adopted plan B. In group A, 120 kV and 80 mL contrast agent dosage were used for FBP image reconstruction; in group B, 100 kV and 65mL contrast agent dosage were used for KARL 3D grade 5 and FBP image reconstruction respectively. We compared the subjective grade, objective evaluation and radiation dose difference of the image quality between the two groups. Results: There was no statistically significant difference in KARLl 3D grade 5 reconstruction image qualities between the two groups, and both groups met the diagnostic requirements of CTA. Compared with the FBP image, we found that the noise of the KARLl 3D level 5 reconstruction images in group B decreased and the image quality improved, the difference held statistical meaning. The effective dose of group B was lower than that of group A, and the difference held statistical meaning. Conclusion: The bronchial artery images obtained by using low tube voltage and low contrast agent dosage based on KARL 3D iterative reconstruction algorithm can meet the diagnostic requirements and in the mean time reduce the radiation dose and contrast agent dosage used on the patients.