A novel extracellular multifunctional GH3 enzyme (Bgxaf3) from fungal source was firstly characterized by homologous over-expressing a putative GH3 β-xylosidase encoding gene bgxaf3 from P.oxalicum.The purified Bgxaf3 predominantly presented β-glucosidase activity and also displayed the activities of β-xylosidase/α-arabinofuranosidase.The Bgxaf3 exhibited high thermo-stability and high resistance to Fe3+,Zn2+,Mn2+,K+,which different with reported multifunctional enzyme from bacterial C.cellulans sp.21.The multifunctional enzyme Bgxaf3 showed good synergism with P.oxalicum cellulase and effectively enhanced enzymatic hydrolysis of pretreated wheat stover and corncob residues,thus high bioconversion of cellulose and hemicellulose in lignocellulose to glucose and xylose was obtained.All these favorable characteristics make Bgxaf3 an interesting candidate for optimization of a better cellulase cocktails to decrease the enzyme cost and enhance crude cellulase efficiency for the bioconversion of lignocellulosic biomass.