Abstract: Objective: To evaluate image quality and radiation dose for coronary artery computed tomographic angiography(CTA) obtained with 80 kV. Methods: 61 patients enrolled in this study were randomly divided into two groups. The group A was 32 patients with tube voltage 80 kV and tube current(200-350)mA. The group B was 29 patients with tube voltage 120 kV and tube current(300-450)m A. Two groups were evaluated for the image quality score, mean attenuation, noise, signal-to-noise ratio(SNR) and contrast-to-noise(CNR) in aortic root and radiation dose. The image quality and radiation dose was compared by Chi-square test and unpaired t-test. A P value below 0.05 was considered to be statistically significant. Results: The aortic root showed significantly higher mean image quality score, mean attenuation, noise and CNR in group A than in group B(P = 0.000, P = 0.000, P = 0.000, P = 0.047, respectively). The SNR was not statistically significant for group A versus group B(P = 0.471). The percentage of assessable coronary artery segments was no statistically significant for group B versus group A(χ²= 3.276, P = 0.070). The mean effective dose was statistically significant for the group A was 0.95 mSv versus 2.07 mSv for the group B(t =-28.052, P = 0.000). Conclusion: 80 kV-CTCA with higher tube current could offer assessable image quality and substantially reduced effective radiation dose.