MicroRNA (miRNA) are highly conserved, non-coding, short, single-chain RNA (～22 nt), and play essential roles in regulating gene expression. Many studies have shown that circulating miRNA profiles are significantly varied in different clinical types of coronary artery disease (CAD), which indicates that miRNA may be a new kind of diagnostic biomarker for CAD. In this paper, the research progress in circulating miRNA in diagnosing CAD was reviewed, so as to provide a basis for their application as promising diagnostic biomarker for CAD.