Abstract: The characterization of the intracellular β-glucosidase from Paecilomyces sp.FLH30A including substrate specificity, kinetic properties, transglycosylation activity and activation and inhibition were studied. The results showed that the optimum temperature and pH of the enzyme glucosidase were 60℃ and 6.0, respectively. Its residual activity was more than 80% after being treated at 70℃ and pH5.0¹2.0 for 30min.The β-glucosidase was a single subunit protein with molecular mass of 57.2ku. The enzyme exhibited a broad substrate specificity and significantly hydrolyzed p- nitrophenyl- β- D- glucopyranoside, pNP- α- D- Glucopyranoside, pNP- β- D-galactoside, ONP-β- D- galactopyranoside, cellobiose, gentiobiose, lactose and cellooligosaccharide, moreover, it displayed substantial activity on β- glucans such as barely- β- glucan, laminarin and lichenan. Furthermore, the enzyme showed transglycosylation activity.