Baculovirus chitinase gene (ChiA) is a late gene and is essential for liquefying host insect at the late stage of infection for its hydrolyzing chitin function. In previous report, baculovirus ChiA can offer many interseting new opportunities for pest control. Recently, a putative chitinase gene (ChiA) was identified in the Spodopter litura nucleopolyhedorvirus (SlMNPV-K1) genome. The open reading frame (ORF) contains 1,692 nucelotides (nt) and encodes a protein of 563 amino acids (aa) with a predicted molecular weight of 62.62 kDa. To conform the insecticidal activity of ChiA from SlMNPV-K1, we constructed a baculovirus transfer vector, pBac-SlChiA, and this transfer vector was co-transfected with the bApGOZA DNA into sf9 cell to generate corresponding recombinant viru which designed Ap-SlChiA. Western blot analysis indicate that SlMNPV-K1 ChiA was successfully expressed. We found the chitinase activity of recombinant virus was enhanced 53% than wide type AcMNPV by chitinase assay, and the recombinant virus showed higher evidently insecticidal activity against 3rd instar larvae of Spodotera exigua than wide type AcMNPV (4.5 time). These results suggested that the chitinase gene from SlMNPV-K1 could be successfully applied to improve pathogenicity of bauclovirus