More and more foreign genes have been expressed in the silkworm larvae or silkworm cell lines using the Bombyx mori nuclear polyhedrosis virus (BmNPV) as a expression vector.The expressed products involve in many fields such as pharmaceutics, medical diagnosis, vaccine production and biological control. The characteristics of BmNPV and its genome structure,characteristics of polyhedrin gene,construction of recombinant BmNPV and its expression in the silkworm larvae and cell line, and efficiency of production for the foreign gene products expressed in the silkworm-BmNPV system and application of the expressed product were described systematically in the review.