Buprofezin and imidacloprid are selective insecticides against Homoptera insects. This paper investigated stimulating effect of the two insecticides on the number of laid eggs by yellow rice borer, Tryporyza incertulas(Walker) of three generations in 20012002. The results showed that the reproductive rate of emergence months during the larvae feeding on the rice plants of Xiushui63 treated with the two insecticides was significantly higher than that of control, indicating that the numbers of laid eggs by the borer was stimulated following buprofezin and imidacloprid applications. However, there was no such effect for the larvae feeding on rice variety Zhendao2 which showed moderate resistance to the insect. In addition, the incidence of stimulating egg laid for the first instar treated with the two insecticides was greater than that for the third instar. Biochemical tests showed that oxalic acid concentration declined, and photosynthetic rate of rice leaves following the two insecticide applications declined significantly compared to control, whereas reducing sugar concentration increased significantly for all other treatments of two varieties except Xiushui63 treated with buprofezin. The level of glutathione-S-transferase varied with rice variety and insecticide. Buprofezin and imidacloprid are selective insecticides against Homoptera insects. This paper showed that the two insecticides on the number of laid eggs by yellow rice borer, Tryporyza incertulas (Walker) of three generations in 20012002. The results showed that the reproductive rate of emergence months during the larvae feeding on the rice plants of Xiushui63 treated with the two insecticides was significantly higher than that of control, indicating that the numbers of laid eggs by the borer was stimulated following buprofezin and imidacloprid applications. However, there was no such effect for the larvae feeding on rice variety Zhendao2 which showed moderate resistance to the insect. In addition, the incidence of stimulating egg laid for the first instar treated with the two insecticides was greater than that for the third instar. Biochemical tests showed that oxalic acid concentration declined , and photosynthetic rate of rice leaves following the two insecticid e applications evaluated significantly compared to control, whereas reducing sugar concentration increased significantly for all other other treatments of two families except Xiushui63 treated with buprofezin. The level of glutathione-S-transferase varied with rice variety and insecticide.