Abstract: Circular RNAs(circRNAs) are a large class of RNAs that form covalently closed continuous loops. They are the members of the non-coding RNAs. circRNAs are characterized by evolutionally conserved, relatively stable, highly specific and enormously abundant. They can regulate miRNA activity as “miRNA sponges” and have an effect on gene transcription and the generation of proteins. circRNAs are gradually becoming a new star of the ncRNA regulatory network. They are involved in the development of numerous diseases and have great potential in the diagnosis, treatment and prognosis of tumors. circRNAs are expected to become new tumor biomarkers or molecular therapeutic targets.