Objective: To detective the expression and characteristics of plasma microRNA-214 (miR-214) in patients with coronary artery disease (CAD) and find the relationship between miR-214 and onset time, level of stenosis and scores of Gensini. Provide the basis for miR-214 become a new CAD diagnostic biomarker and drug target. Methods: Thirteen cases of acute myocardial infarction (AMI) patients and 27 cases of healthy volunteers were compared; 22 cases of CAD patients with chest pain and 8 cases of non-CAD patients with chest pain were compared; 154 patients with complex coronary artery lesions in patients with acute chest pain and 92 patients without coronary artery stenosis in patients with acute chest pain were compared. All cases’ miR-214 expression and concertation of cardiac troponin-I (cTnI) were measured. Analyze the miR-214’s relationship with the time of AMI onset time, the degree of coronary artery stenosis, and Gensini score of CAD patients. Results: miR-214 was enriched in the plasma of CAD patients. Compared with the healthy control, the miR-214 in AMI patients significantly increased after AMI onset (P<0.05), the plasma miR-214 level in AMI patients was positively correlated with cTnI concentration (r=0.596, P<0.05); the level of plasma miR-214 was positively correlated with degree of coronary artery stenosis in CAD patients (r=0.554, P<0.05); miR-214 level and CAD Gensini score was positively related (r=0.480, P<0.001). Conclusion: Circulating miR-214 may be a new biomarker and a potential diagnostic tool for CAD, and increased miR-214 level may be used to predict the presence and severity of coronary lesions in CAD patients.