Abstract:A 762 bp mite (Pyemotes tritici) insect-specific neurotoxin tox34 gene fragment encoding mature protein was fully modified based on plant gene codon usage, tox34 was inserted into bacterial expression vector pBV221. Electrophoresis of protein mixture extracted from the bacteria treated with heat-induction showed that specific protein bands migrated with apparent molecular weight of 32 ~ 33 kD in denaturing gels. Tox34 was inserted into plant high-expression vector and then transferred into tobacco (Nicotiana tabacum L. cv. SRI ) using the Agrobacterium tumefaciens (Smith et Tomnsend) Conn binary vector system, followed by the obtainment of the transgenic tobacco plants. The PCR Southern blot assay indicated that the intact toxin gene was integrated into the tobacco genome. GUS assay of transgenic seedling roots showed positive results. The feeding trail of transgenic plants using bollworms (Heliothis armigeva Hubner) manifested strong toxity to lowstar bollworm larvae.