Dendrolimus kikuchii Matsumura nucleopolyhedrovirus (DkNPV) is a novel nucleopolyhedrovirus strain that has been exhibited high potential as biological control agent against D.kikuchii.In this work,a 1674-bp CkChi gene with sequence homology to chitinase gene was cloned from the genomic DNA of DkNPV using the DNA fragment library.The CkChi gene encoding 558 residues protein with a theoretical molecular mass of 60.6kDa was expressed to high levels in E.coli and purified by affinity chromatography.We confirmed that the prepared protein was the CkChi protein by mass spectrometry analysis.Enzyme activity analysis indicated that CkChi protein could efficiently hydrolyze 4-MU-(GlcNAc)3 substrate with optimal catalytic conditions of 35℃ and pH6.0.When the third instar larvae of Hyphantria cunea were fed on an artificial diet supplemented with the recombinant CkChi,83% mortality was observed at a dose of 2μg/g of larval body weight (LW),while at sub-lethal doses of 1.05μg/g LW,a reduced larval growth was recorded.The results suggest that CkChi is a good candidate protein for significantly contributing to the development of pest control.