Abstract: In comparison to the commercial insecticide diflubenzon,the insecticidal activities of six novel benzoylphenylurea compounds against the fourth instar larvae of Mythimna separata Walker and the larvae of Culex pipiens pallens were investigated in laboratory.The results indicated that compound 1a showed same insecticidal activity against Mythimna separata Walker as difoubenzon.The median lethal concentrations of 1a-1f for Mythimna separate Walker were 1.84, 4.85, 9.20, 70.79, 18.88, 23.12 respectively,vs 1.82 for diflubenzon. Likewise,the insecticidal activities of 1a,1b against the larvaes of Culex pipiens pallens were markedly higher than that of diflubenzon.The median lethal concentration of 1a-f for Culex pipiens pallens were 0.00086,0.00175,0.00852,0.0160,0.00680,0.02270,0.00958 respectively,vs 0.0160 for diflubenzon.In conclusion,compounds 1a-c exhibited good insecticidal activities against Mythimna separata Walker and 1a-b showed excellent insecticidal activities against Culex pipiens pallens.