Based on life table and the interference iodex of population control,the effects of the different insecticides aod the different applications of Insecticides were evaluated in this paper. The effect of Dimehypo on the population of the paddy borer was the best,and Quinaphos was better than Dimilin- I.Tbe effects of different applications of Chlorodimeform was evaluated by the successive life table. The results showed that root-zone application was much belter than the spraying.