This research construct the soil metagenomic library， which have 1.3×104 storage capacity and 30 Mb length of the total gene. Screening the positive clone can hydrolyze xylan from the library based on the functional strategy. Sequence analysis revealed that cbxynA potential encoding xylanase gene with 822 bp length. Only 45% of its amino acid sequence similar with the encoding xylanase from Halobacteriaceae archaeon（Archaea）， which indicated that it’s a novel unknown sequence. Molecular weight of cbxynA expressed in the E.coli was 29 ku consistented with predicted size. At the same time， the prokaryotic expression conditions were optimized. The results showed that the plasmid cultivated for 5 h， then added 0.7 mmol/L IPTG at 23 ℃ inducing for 25 h， and the xylanase activity was 52 U/mL. The optimum pH and temperature of the recombinant enzyme CBXYNA were 5.2 and 55 ℃， respectively. The metal ions of Na+， K+， Li+ and Ca2+ can enhance the enzyme activity. While Mg2+， Mn2+， Zn2+， Fe3+， Al3+ and Cu2+ can inhibit the activity of the enzyme. When CBXYNA taken water soluble corncob xylan and oat xylan， water-insoluble corncob xylan as substrate， the relative enzyme activity was 162%， 139%， 74%， respectively.