The purpose of the research was to evaluate the diagnostic performance of microRNA-299-3p (miR-299-3p) in patients with coronary artery disease (CAD). The relative abundance of miR-299-3p in patients with CAD was verified by quantitative real time polymerase chain reaction (qRT-PCR) assay. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for analysis, and target genes were predicted and enriched by DAVID software. The protein-protein interaction (PPI) network was drawn by STRING database. Receiver operating characteristic (ROC) was adopted to appraise the diagnostic value of miR-299-3p in CAD. Bioinformatics analysis showed that the GO function of miR-299-3p target genes of miR-299-3p mainly focuses on specific granular membrane, regulation of apoptotic signaling pathway, growth factor binding and so on. KEGG analysis showed that the most abundant pathways involve fluid shear stress and atherosclerosis, as well as Notch signaling pathways. PPI network showed the seven predictive genes encoding the proteins play pivotal roles in maintaining the stability and interaction of the network, especially matrix metallopeptidase 2 (MMP2) and intercellular cell adhesion molecule-1 (ICAM1). Compared with the control group, serum miR-299-3p in the CAD group was distinctly up-regulated via qRT-PCR (p < 0.001). ROC analysis showed that miR-299-3p was an important index for detecting CAD patients and major adverse cardiovascular events (MACE) patients with an AUC of 0.931 and 0.758, respectively. MiR-299-3p is involved in the development of CAD, and might become a potential biomarker for monitoring CAD.