Circular RNA (circRNA) is widely found in various species' cells.They have several characteristics including structural stability,high expression and expression in a tissue-specific manner.Recent studies have demonstrated that circRNA is a member of competing endogenous RNA (ceRNA).CircRNA regulate the expression of related RNA molecules via binding with target microRNA (miRNA) and play an important role in gene expression and regulation.The finding of circRNAs not only expand our understanding about eucaryon and ceRNA regulation network,but also indicate that circRNA might be a new biological marker for diagnosis and has good application prospects in drug development research,and disease diagnosis and treatment.Because current research on circRNA is still very few,a brief summary about circRNA is presented in this paper for further research.