A new cationic asphalt emulsifying agent was synthesized by neutralization oftrimethylamine solution(33%)with fatty acids,and then esterification of this products withepichlorohydrin was made. The emulsifying effect of the emulsifying agent on Shengli 100#road asphalt was in vestigated.The result shows that the emulsifying performance is as good asNOT,and with simpler synthesis technology this method may have a better applicationfuture.