Abstract: The components and act iv ity of digestive enzymes ex tracted from larvae o fM onochamus alternatus, larvaeand adults o fTomicus p inip erda w ere ana lyzed in this paper. The results revealed tha,t there w ere 10 digestive en-zymes in Monochamus alternatus and 8 in Tom icus p inip erda. The activ ity order o f enzymes o f larvae ofMonochamusalternatus arranged as pectinase> amy lase> endo-β-1, 4-g lucanase ( Cx-ase) > hem icellu lase> invertase> -1, 4-glucosidase> exo-β-1, 4-g lucanase ( C1-ase) > lipase> trypsinlike enzym e> pepsin; and for larvae and adu lts ofTomicus p in ip erda, the activity order of enzymed arranged as pectinase> amy lase> hem ice llulase> invertase> exo-1, 4-glucanase( C1-ase) > trypsin like enzyme> lipase> pepsin. There w ere no Cx-ase and -1, 4-g lucosidase forboth larvae and adu lts o fTom icus p iniperda. The resu lt pect inase had the h ighest act iv ity under 55℃ and pH= 8. 6.