Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.