The study on disruption of Spodoptera litura Fabricius is conducted in the cornfield in Yunlin County from Jul. 2014 to Apr. 2015 by means of synthetic sex pheromone of Spodoptera litura Fabricius as the mating disruption agent. The disruption agents used in the study include (Z,E)-9,11-TDDA, (Z,E)-9,12-TDDA and a mixture of (Z,E)-9,11-TDDA and (Z,E)-9,12-TDDA in the ratio of 10:1. The result was shown that (Z,E)-9,12-TDDA, the minor component of Spodoptera litura Fabricius sex pheromone, has the best effect as the mating disruption agent. The average disrupting ratio is 87%, and can reach 100%. In the study, the more the agent is applied, the better the disrupting effect shows.