Abstract: This paper studied β-xylosidase activity and xyl gene expression in different strains of Volvariella volvacea. Bioinformatics traits of Xyl were analyzed. Xylosidase activities in different Volvariella volvacea strains were determined by 4-Nitrophenyl-β-D-xylopyranoside. The xyl gene expression was measured by real time-PCR using GAPDH as the reference gene. Results showed that Xyl belonged to glycoside hydrolase family 43 and consisted of 534 amino acid residues. The predicted molecular weight and isoelectric point of Xyl was 58.82 ku and 4.99, respectively. Phylogenetic analysis indicated that Xyl was similar with wood rot fungi at61% level. Xyl in Volvariella volvacea was much closer to that in wood rot fungus Phanerochaete chrysosporium or Stereum hirsutum than to the homologous sequence in grass rotting fungus Coprinopsis cinerea. Xylosidase activity in Vb1 was the highest;however, no significant difference of xylosidase activity was observed between0229 and A8. The real time-PCR analysis showed that relative expression of xyl gene in different strains of Volvariella volvacea was Vb1>A8>0229.