Abstract： Objective To investigate the preparation of cationic polymeric liposomes (CPL) carrying short hairpin RNA (shRNA) plasmid and its physicochemical properties,and to determine the optimal coupling ratio,and to further improves the cell transfection protocol.Methods CPL was established for characterization.The effect of CPL on cell proliferation was determined by methyl-thiazolyl-tetrazolium (MTT) colorimetric assay.CPL were coupled with shRNA plasmid,and divided into the control group (without any intervention),Lipofectamine2000 transfected group and pCPL-shRNA group [different mass ratio of shRNA plasmids coupled with CPL (1 ∶ 0、1 ∶ 0.5、1 ∶ 1、1 ∶ 1.5、1 ∶ 2、1 ∶ 2.5、1 ∶ 3)].The human colon cancer cell line HCT-116 cells were transfected.The transfection efficiency of CPL carrying shRNA plasmid was determined by flow cytometry.Results The established CPL was substantially spherical,with uniform size,smooth surface,and well-dispersed nanoparticles [average particle diameter (95.58±4.21) nm].The cell inhibition rate gradually increased along with the increasing CPL concentration,showing linear correlation (R2=0.9851,P＜0.05),IC50=7.605× 10-2 g/L.The optimal coupling ratio of shRNA plasmid and CPL was 1∶2,and the transfection efficiency was (28.19±5.38)％,which was better than that in the transfection agent Lipofetamine group [(21.33±6.11)％] (P＜0.05).Conclusion The established CPL carrying shRNA may be an ideal gene delivery carrier.