Using vinegar as the main raw material to produce xylanase by solid-state fermentation of Neurospora sitophila. Using the activities of xylanase as indicators, the medium and culture conditions were optimized by single factor experiment and orthogonal experiment. Results: The medium consisted of 5 g of vinegar and 0.4 g of bean dregs. The initial pH of the medium was 5.5, 106 spores/Bottle of inoculum concentration and the solid-liquid ratio was 13 (g/mL), and the culture medium was cultured at 28 ℃ for 3 d. The enzyme activity was 412.34 U/g under the optimized conditions, which was increased about 3.59 times than that before optimization (114.95 U/g).