Abstract: As a catalytic DNA molecule obtained by in vitro selection, DNAzyme has the advantages of high stability, good specificity, cost-effectiveness and no immunogenicity.Among DNAzymes, the one with RNA-cleavage activity mimics the function of ribozyme in biology, which has attracted particular attention for tumor theranostic applications.This paper describes the basic information of DNAzyme, including its screening process, the mechanism of RNA cleavage and the representative DNAzymes, and introduces the application of DNAzyme in RNA interference, tumor multi-model synergistic therapy, tumor theranostics and stimulus-responsive drug delivery, with a prospect of their potential applications in this field and future development so as to provide reference for the clinical translation of DNAzyme.