Abstract:Plutella xylostella L.and Pieris rapae L.are the main pests of pakchoi. Inducing anti-insect gene into pakchoi and breeding anti-insect plants by transgenic technique will be an effective way to solve the serious problem. Pakchoi growing for 45 days with flower-stem were used as material for agrobacteria mediated vacuum infiltration transformation. The plant expression vector carried gene bar and a potato wound-inducible proteinase inhibitor II (pin II) gene. Transgenic plants were selected by spraying with Basta solution on seedlings of the harvested seeds from the infiltrated plants. Forty-two transgenic plants were confirmed by Chlorophenol red test,PCR and genomic Southern blotting. Bioassay of insect resistance in the second-generation of individual lines of the transgenic pakchoi plants showed that the developments of larvae fed with transgenic leaves were retarded,and weights of the pupas were lighter than the control.