Objective To discuss the correlation between the left anterior descending coronary artery myocardial bridges(LAD-MB)and coronary atherosclerosis.Method CTA data of 254 cases with LAD-MB(199 cases with complete MB in group A,55 with incomplete MB in B)and 569 cases without MB(control group C),from May 2013 to May 2014 in our hospital,were analyzed retrospectively.LAD-MB was shown with the techniques of three-dimensional volume rendering(VR),curved plane reformation(Curved)and multi-planar reformation(MPR).The incidence of coronary atherosclerotic plaques was calculated and characteristics of plaques on LAD were observed.The chi-square test was used.Result 269 sites of LAD-MB were detected in 254 cases,of which 85.9%were located at the mid LAD.Atherosclerosis incidence of LAD,PDA,LCX in A,B,C groups was 51.8%,47.3%,47.5%; 32.2%,25.5%,28.1%; 29.6%,20%,20.9%,respectively.The quantity of calcified plaque,noncalcified,mixed in A,B,C groups was 36,24,43; 6,9,11; 124,64,82; the calcium score and maximum area of noncalcified plaques in A,B,C groups were 179.59±61.98,195.57±76.9,168.4±90.12; 30.48±15.73 mm2,22.17±10.30 mm2,28.82±13.84 mm2,respectively.The atherosclerosis incidence of LAD proximal-MB,MB,distal-MB in A and B groups was 51.8%,0.5%,4.5%and 47.3%、0%、1.8%.There were significant differences in the proximal-MB,MB,distal-MB of LAD,but no difference between group A and B.Atherosclerosis incidence of proximal,middle,distal segment of LAD in group A,B,C were 44.7%,19.1%,2.5%; 36.4%,20%,1.8%; 40.2%,26.7%,0.5%,respectively.There was no significant difference in the proximal segment between group A+B and C,but there was statistical difference in the middle and distal(P<0.05).Conclusion LAD-MB would neither influence the atherosclerosis incidence of coronary artery,nor change the characteristics of plaques.Atherosclerosis incidence of patients with MB is more on the proximal-MB than on the MB or distal-MB of LAD.Compared to patients without MB,that of patients with LAD-MB is lower on mid-segment and higher on distal,which would cause left ventricular apex and inferior wall ischemia.