A Gemini quaternary ammonium salt fabric softener with ester bond was synthesized from 2-dimethylaminoethanol, stearic acid, octadecyl dimethyl amine(DMA18), hydrochloric acid and epichlorohydrin(ECH). The effects on the reaction process were investigated by the single factor and orthogonal experiment. The optimum conditions of dimethyl stearic acid ethyl tertiary amine were obtained as follow: n(2-dimethylaminoethanol):n(stearic acid)=1.15:1, reaction temperature 100℃~110℃, reaction time 7h, , m(toluene):m(2-dimethylaminoethanol)=1.3:1, w(sub-phosphoric acid)=1.0%, the yield is over 96.6%; The optimum conditions of intermediate ammonium chloride were obtained as follow: n(ECH): n(DMA18)=0.95:1, w(isopropyl alcohol)=50%, reaction temperature 40~50℃, reaction time 60 min, the yield is above 90.9%; The optimum conditions of ester Gemini quaternary ammonium salt fabric softener were obtained as follow: n(intermediate ammonium chloride): n(dimethyl stearic acid ethyl tertiary amine)=1:1.1; reaction temperature 100℃; reaction time 10h, the yield is beyond 95.3%. The synthesis had been proved successful in Henan Titaning chemical Co.Ltd in a 500L pilot test.