Cationic gemini surfactant dimethylene-1,2-bis(dodecyldiethylammonium bromide), referred to as C12C2C12(Et) was synthesized, and its surface property and aggregation behavior in aqueous solution were studied. The value of γat the critical micelle concentration (γcmc) is much smaller than that of the surfactant homologues with longer spacer. Spherical and elongated micelles were formed in the aqueous solution of this gemini surfactant,and the spherical micelles were absolutely dominant compared to the elongated micelles at our studied concentration quantitatively.