Abstract: Synthetic sex pheromone was very effective in controlling the population of diamondback moth, Plutella xylostella L.in the green house When the synthetic sex pheromone was used under the low DBM egg density (1-3 eggs/per plant), 70% control effect was obtained Significant difference in control effect was found among different vegetable varieties The control effect in Chinese cabbage and Shanghai Qing was higher, than those in the pakchoi and Chinese kale More male moth was attracted when three sex pheromone traps/180m² were used in the experimental period A control effect of 70% was obtained when sex pheromone was used continuously for 6 plantings of Chinese cabbage.