Abstract: This study aimed to compare the efficiency of salting-out method and aqueous two-phase method in the separation and purification of xylanase from Paenibacillus sp. B1709,and determined the optimal extration methods. A higher recovery of xylanase purification was obtained by the aqueous two-phase extraction and parameters were optimized,the optimum concentrations of PEG4000,(NH₄)₂SO₄,NaCl and pH were 22%,18%,2% and 6,respectively. Under these conditions,the results were achieved as follows:partition coefficient 9.90,enzyme activity recovery 90.84% and the purification factor 6.13.Therefore,the aqueous two-phase has an advantage of a certain technology in the large-scale purification especially for complex purification.