Abstract: Objective To explore the effect of the course and bifurcate angle of left main coronary artery on atherosclerotic plaques formation and distribution. Methods Clinical data about 110 people receiving CT coronary angiography from October 2013 to December 2013 were retrospectively analyzed. All subjects were divided into two groups according to the course of the left main coronary artery (LM): tortuous LM traveling group (42 cases) and no tortuous LM traveling group (68 cases). The bifurcate angle of the LM was measured. The correlation between the course and bifurcate angle of the LM and the occurrence of atherosclerosis were observed. Results Compared with no tortuous group, the incidence of the left coronary artery atherosclerosis was signifcantly higher in tortuous group (P< 0.01), and the incidence of plaques located in the LM or LAD was also higher in tortuous group (P< 0.05), while the incidence of plaques located in the LCX showed no statistically signifcant difference between two groups (P> 0.05). There existed negative correlation between the bifurcate angle of the LM and the plaque from the distance of the bifurcation in 64 patients with LAD lesions (r=-0.314, P< 0.05), while there was no correlation between the bifurcate angle of the LM and the plaque from the distance of the bifurcation in 18 patients with LCX lesions (r=-0.309, P> 0.05). Conclusion Plaque is more easily formed in the left coronary artery with tortuosity or big bifurcation angle which can be a risk factor for atherosclerosis. The bifurcate angle of the LM also plays an important role in the distribution of plaques.