Objective To investigate the clinical value of circulating miR-125b-5p in coronary atherosclerotic heart disease.Methods With case-control study,80 cases of coronary atherosclerotic heart disease were recruited in Affiliated Hospital of Nantong University from February 2014 to august 2015.According to coronary angiography result they were divided into two groups: there are coronary artery stenosis group(n=49)and control group(n=31).All patients were also divided into non-ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction group(n=35),unstable angina group group(n=25),stable angina group(n=20).The level of miR-125b-5p before coronary angiograph was detected.By independent sample t test and variance analysis,the levels of miR-125b-5p were compared between the groups of coronary artery stenosis and the group with no stenosis of the coronary artery,the coronary artery lesions in each group,and between the various types of coronary atherosclerotic heart disease respectively.Results MiR-125b-5p expression level of Coronary artery stenosis group(0.35±0.10)was lower than that in group coronary artery with no stenosis(0.95±0.12),the difference was statistically significant(t=24.179,P<0.000 1).With the increase in the number of diseased coronary arteries,miR-125b-5p expression level decreased gradually.There is also statistical significance(t=8.399,P<0.000 1; t=13.067,P<0.000 1)in miR-125b-5p expression among NSTEMI+STEMI,UA and SAP groups.miR-125b-5p expression level was negatively correlated with Gensini score(R2=0.822,P<0.05).The area under the ROC curve(AUC)of miR-125b-5p was 0.86(95％CI 0.67-0.90),and 0.66 was the optimal cut-off value with sensitivity of 81.22％and specificity of 78.62％.Conclusions With the increase of the number of stenosis,plasma miR-125b-5p expression level decreased gradually.The expression level of miR-125b-5p was negatively correlated with the Gensini score of coronary artery,which indicated that the expression level of miR-125b-5p may be a potential biomarker that can reflect the lesion degree of coronary artery.