Isocitrate lyase (ICL) which plays a pivotal role in the glyoxylate cycle of mycobacterium tuberculosis(MTB) could be a potential target against mycobacterium tuberculosis.Deoxyribozyme(DRz) is a small single-strand,enzymatic DNA molecule.Assistant by sketch of secondary structure,appropriate and not appropriate target sequences of MTB ICL mRNA were predicted.Two DRzs were designed targeting above sequences respectively.To affirm feasibility of this kind of prediction,in vitro cleavage of MTB ICL mRNA segment by DRz-ICLcf and DRz-ICLcj were performed.The results showed that sketch of secondary structure could indeed predict potential target of DRz.This research will provide basis for developing DRz as a novel antimicrobial agent against MTB.