Abstract: mg/g fenvalerate and 2mg/g phenobarbital (PB) mixed in diet seperately caused different induction of cytochrome P450 in different tissues of susceptible strain (HDS) and resistant strain (KQR)of Helicoverpa armigera Hübner. The two inducers can caused significant induction of cytochrome P450 in midgut, fatbody and integument of HDS strain ,the maximum levels of induction in three tissues was 2.24 ,2.03 , 1.60 fold by PB respectively and was 2.14 ,2.83 , 1.28 fold by fenvalerate respectively . PB and fenvalerate can also induce cytochrome P450 in some tissues of KQR strain, but the effect was much less than that of HDS strain, the maximum induction of PB was 1.21 fold in midgut and 1.72 fold in fatbody, but for fenvalerate, the induction showed only in midgut (1.15 fold). Besides, the induction also showed the difference of inducer, time effect and tissue spicific.