The enhance effect of oligonucleotide transfection mediated by cationic liposomes (Lipofectin, LipofectAmine, FuGENE6 and DM-R1E-C) were investagated using flow cytometry in Hela cells. Two 19-mer molecules, phosphodiester oligonucleotide (ODN19) and phosphorohieoate oligonucleotides (SODN19), were employed, which are labeled with Fluorescein isothiocyanate(FITC) and have the same sequence. The results show that, for the unmodified ODN19 molecules, LipofectAmine and DMRIE-C can obviously improve the transfection, but no improving effect were observed in other two liposome. For the S-ODN19 transfection, all of the 4 calionic liposomes possess the observed ability to enhance the transfection, of which the LipofectAmine was more efficient than three others. The mean FITC density (5203.11) of LipofectAmine mediated transfection was several decades times comparable to the control cultures without mediated liposome. The improving effect of liposomes mediated transfection was ranked as LipofectAmine FuGENE6 DMRIE-C lipofectin. Meanwhile. The experiment also suggested that, when transfection procedure was performed for about 4 hours, a high efficiency can be expected in FuGENE6 mediated oligonucleotides transfection.