Abstract: MicroRNAs (miRNAs),a series of endogenous,non coding and single strand RNA approximately containing 22 nucleotides,regulate messenger RNAs at the post transcriptional level through binding to complementary sequences in un translated regions (UTR),inducing RNA induced silencing complex (RISC) to degrade mRNA or repress translationA miRNA can have multiple mRNA targets,and the same mRNA can be regulated by many miRNAsLatest researches show that RNAs regulate each other using microRNA response elements (MREs) and this mechanism is known as "competing endogenous RNA" (ceRNA)ceRNAs hypothesis has enabled new features for mRNA and activity forms a large scale regulatory network across the transcriptome,greatly expanding the functional genetic information in the human genome and playing important roles in pathological conditions,such as cancerThis paper reviewed ceRNAs regulating mechanism with the following respects:members of ceRNAs regulatory network,ceRNAs regulating bases,the mechanismm of ceRNAs as well as ceRNAs with tumor.