The synthesis and characterization of a novel macrocyclic polyamine cationic lipid containing an imidazolium salt group is reported. Its interaction with plasmid DNA was studied by gel electrophoresis and fluorescence quenching experiments. The transfection activity of target compound as a gene delivery vector was also investigated. The results showed that the synthesized macrocyclic polyamine cationic lipid has high binding and condensation ability of DNA under physiological conditions probably because of the cooperation effect of macrocyclic polyamine (Cyclen) and an imidazolium salt group. This novel lipid could transfer plasmid DNA into cell in in vitro experiment without the use of any extraneous agent.