Abstract: Chlorantraniliprole, metaflumizone, chlorfenapyr, ProclaimR (banleptm) and diafenthiuron are common insecticides used for controlling diamondback moth, Plutella xylostella. In this paper, the experiments of surface tension test, bioassay analysis in lab, effective duration evaluation in potted and field vegetables were corried out to study the effect of different formulations (EC and SC) of 5 insecticiedes on P.xylostella. The results showed that surface tension values of all EC formulations were lesser than SC formulations, and toxicity of all EC formulations against to P.xylostella were also better than SC formulations. But effect of SC formulations had better stability than EC formulations in the open environment. All the results indicate that different formulations of the same insecticide have different advantages; we should select the appropriate formulation according to the different environmental conditions