Abstract：Novel Vegetative insecticidal protein Vip3A is a non-crystal and extracellular toxic protein secreted outside the cell during Bacillus thuringiensis mid-logarithmic growth.Using Southern blotting of gene localization,vip3A gene was determined neither on chromosome nor annuliform plasmids.The homology of vip3A genes was very high.Furthermore,the blast results of the functional domains among Vip3A protein peptides by the bioinformation soft showed that a similar domain of chemotaxis sensory transducer exists on the N-terminus and a cellulose binding domain on the C-terminus. The mechanism is different from that of δ-endotoxins.