Objective: To investigate factors of dual-source CT coronary angiography image quality and suggest measures to improve the image quality. Methods: Total 300 patients through dual-source CT coronary angiography were randomly selected as control group from January 2009 to January 2011,and were divided into Ⅰto Ⅳ from priority to poor compared with similar studies according to quality of evaluation criteria,then factors of dual-source CT coronary angiography image quality were analyzed. Meanwhile,300 patients through improved measures were randomly selected as modified group from February 2011 to August 2011. Results: The image quality in control group were grade Ⅰ:232 cases(77.3%);grade Ⅱ:48 cases(16.0%);grade Ⅲ:16 cases (5.3%);grade Ⅳ:4 cases(1.3%);the factors of dual-source CT coronary angiography image quality were severe coronary artery calcification,respiratory artifacts,severe arrhythmia artifacts,superior vena cava,right atrium,high-density contrast agent produced artifacts,inappropriate choice of monitoring the level of the trigger points and inappropriate choice of phase reconstruction. The image quality in modified group were grade Ⅰ:263 cases (87.7%);grade Ⅱ:26 patients (8.7%);grade Ⅲ:10 cases (3.3%);grade Ⅳ:1 (0.3%). Image quality grading differences between the two groups were statistically significant(P < 0.01). Conclusion: Optimizing CT scan parameters and proposing appropriate measures,had important significance to improve the quality of coronary imaging.