摘要Objective In order to obtain mature insulin-like growth factor- Ⅱ ( IGF- Ⅱ ), we used Bac-to-Bac baculovirus expression system. Methods Firstly the IGF- Ⅱ cDNA was cloned into a donor plasmid pFastBac1 and the recombinant pFastBac1 was then introduced into competent cells DH 10Bac. Recombinant bacmids were constructed by transposing a mini-Tn7 element from a donor plasmid pFastBac1 to the mini-attTn7 attachment site on the bacmid where the Tn7 transposition functions were provided in trans by a helper plasmid, and then used to transfect Sf9 insect cells to get recombinant baculovirus. The recombinant baculovirus was used to infect insect cells. Results Agarose gel analysis showed that recombinant donor plasmid pFastBac1 was constructed successfully; Agarose gel analysis of PCR products confirmed recombinant bacmid ; SDS-PAGE and Western Blotting showed that a 7KD protein band appeared. Conclusion The mature IGF- Ⅱ with immunogenecity has been expressed and produced by using Bac-to-Bac expression system.