Abstract: Arabinoxylan is found in the cell wall of a wide variety of cereal. Arabinoxylan in wheat flour could compete with the gluten protein for water absorption in the dough, which would increase the hardness of the dough. The xylanase is a key enzyme in the xylanolytic enzyme system and is widely applied in industries including pulp and paper, animal feed, beverages and food. However, the complex structure of arabinoxylan makes most xylanases have limited activity to degrade it. In order to discover xylanase with high arabinoxylan hydrolysing activity, we screened arabinoxylan-degrading microorganisms from soil. We screened for a fungus, designated FAHD19, was identified as Aspergillus capensis. The xylanase from Aspergillus capensis, named AcXyn, was purified to electrophoretic homogeneity through ammonium sulfate precipitation and strong anion-exchange chromatography. We characterised its enzymatic properties and the results showed that the molecular weight of AcXyn was 16.6 kDa. The purified xylanase showed the optimal temperature of 55 ℃, and pH 6.0 with a stable xylanolytic activity within the temperature range of 25-50 ℃, and within the pH range of 5.0-11.5. AcXyn demonstrated good tolerance to various metal ions and chemicals. The presence of Co²⁺ enhanced xylanase activity. but SDS showed inhibition of xylanase activity. It exhibited strict substrate specificity, and had the highest specific activity of 367.9 U/mg towards wheat arabinoxylan. Hydrolysis property analysis revealed that AcXyn degraded arabinoxylan into low-molecular-weight xylooligosaccharides with degrees of polymerization from 4 to 6. AcXyn hydrolyzed xylotetraose to xylooligosaccharides(XOSs) with lower degree of polymerizations(DPs) than itself, but could not hydrolyze xylobiose and xylotriose. In this study, we reported a new xylanase-producing strain that enriches the source of xylanase from Aspergillus species. The AcXyn produced by Aspergillus capensis had excellent arabinoxylan degradation capacity and enzymatic properties suitable for baking processes, which made it potentially valuable for applications in food processing.