Circular RNA ( circRNA) , a novel type of endogenous non-coding RNA ( ncRNA) , has been broadly taken into account during recent years as a research hot-spot.Unlike linear RNA, circRNA form covalently closed loop structure by jointing 3′and 5′ends together via exon circularization or intron circularization.Through which way it is more stable and conserved than linear RNA.Besides, circRNAs are abundant and multiple existences in creatures have been revealed.Nowadays, an increasing number of researchers have found that circRNA plays an essential role in the regulation of gene expression, which has broadened the view of di-verse endogenous noncoding RNA, and therefore hints that circRNA has great potential in clinical diagnosis and treatment of disease. In this paper, we make an overview of the latest research about circRNAs from the aspects of generation, character, function, and the relationship with diseases, and so on.