A kind of asymmetric twin-tailed cationic surfactant has been synthesized by acylation and quaternization using N,N-dimethyl propyl diamine, bromote-tradecane and carboxylic acid as the starting materials. The structures of the intermediate products and the title products were characterized by means of IR and 1H NMR. The optimum conditions for acylation were as follows: n(caprylic acid)﹕n(N,N-dimethyl propyl diamine) = 1﹕1.1，temperature of oil bath was 120℃ and react time was 10h. The surface tension could decrease to 20～30mN•m-1 and the critical micelle concentration (cmc) was found to be 10-5～10-6mol•L-1, which were all far lower than those of the corresponding traditional quaternary ammonium salt. The foam half time was 22～31min. The foam of the asymmetric twin-tailed cationic surfactants was steadier than that of the traditional quaternary ammonium salt.