A new intracellular gene delivery system based on oligochitosan (COS) was prepared and proven to be effective. First of all, The DNAzyme targeting EGFR (EGFR DRz) was designed and synthesized. Then, the biological effect of the EGFR DRz delivery system based on COS was studied in Hela cell with Flow Cytometry. It was shown that there was no statistically significant difference in transfection efficiency between liposome transfection reagent (89.7%)and COSEGFR DRz (88.7%) . The results of semiquantitative RTPCR confirmed that the EGFR mRNA in Hela cell could be cleaved by targeting COSEGFR DRz. The cell cycle analysis in Hela cells transfected with COSEGFR DRz revealed an arrestment in the G0/G1 phase. And the cell apoptosis rate induced by COSEGFR DRz was 19.3%, which was higher than the rate induced by liposomeEGFR DRz (13.0%). These results have demonstrated that COS possesses higher transfection efficiency and lower cytotoxicity. It will be a potential DNAzyme delivery system.