Abstract: In this study, the fermentation technology of xylanase produced by Aspergillus niger in solid-state fermentation using rice crust as a sole substrate was investigated. On the basis of single factor experiment, the best carbon source, fermentation time and content of water for xylanase production by Aspergillus niger were optimized by Box-Benhnken design, and a quadratic regression equation for the change of enzymic activity with soluble starch, fermentation time, the content of water was established. The results showed that the optimal conditions were fermentation time for 78h, the content of water 57%, soluble starch 1.3g. Under optimization conditions, xylanase activity reached 221.5U/g, increased 1.76 times than before optimization.The prediction model indicated high reliability, which could be applied to optimization of xylanase fermentation conditions.