Abstract: A low molecular xylanase ( McXyn25) from Malbranchea cinnamonmea S168 was purified and characterized. The xylanase was purified to homogeneity by ammonium precipitation and anion- exchange chromatography with a subunit molecular mass of 25 ku.The xylanase was most active at pH8.0 and 65℃, and was stable within pH 4.5~11.0 and up to 60℃.The xylanase displayed strict substrate specificity, indicating that the enzyme had potential application prospect in pulp bleaching.Moreover, the enzyme hydrolyzed various xylans to yield mainly xylooligosaccharides without xylose.Therefore, it may be suitable for the production of xylooligosaccharides.