Objective To investigate the relationship of the length of the left main coronary artery (LM) and left anterior descending artery-left circumflex artery (LAD-LCX) bifurcation angle with the atheromatous plaque formation. Methods A retrospective analysis was made of the clinical data of 372 patients admitted to the Second Hospital of Qinhuangdao from January 2020 to January 2022, who underwent CT angiography (CTA) and had clear results. According to CTA findings, the patients were divided into group with lesion at the left coronary artery (lesion group) (n=244) and normal group (n=128). The groups were compared in LMCA length, LMCA area, LM-LAD angle of the left coronary artery origin, LM-LCX angle and LAD-LCX angle. The relationship between LMCA and LAD-LCX bifurcation angle and atheromatous plaque formation was analyzed. SPSS statistics 22.0 was used for statistical analysis. Data comparison between two groups was perfomed using t test or χ²test depending on data type. Results The LAD-LCX angle in the normal group (77.70°±5.78°) was lower than the proximal group (79.23°±5.11°) and the distal group (81.24°±6.96°), and the LAD-LCX angle in the proximal group was lower in the distal group, the differences being statistically significant (P<0.05 for all). Additionally, the LAD-LCX angle in the normal group (77.70°±5.78°) was lower than the mild stenosis group (79.10°±5.05°) and the moderate to severe stenosis group (81.07°±6.32°), and the mild stenosis group had a lower LAD-LCX angle than the moderate to severe stenosis group, the differences being statistically significant (P<0.05 for all). Conclusion The greater the LAD-LCX bifurcation angle, the higher the risk of arterial plaque formation.