Abstract: The influence of carbon sources, nitrogen source, mineral salt on xylanase activity producted by Monascus M2 in the solid state fermentation was studied.On the base of single factors experiments, response surface analysis was applied to optimize the solid state fermentation medium of Monascus M2 for xylanase production.The quadratic regression analysis was applied to get the optimal level of main factors ( corn meal, beef extract, K 2 HPO 4) .Finally determined the optimal medium as follows: corn meal 1.90g, beef extract 0.55g, K 2 HPO 4 0.10g.Under these optimal conditions, the predicted and experimental production of the activity of xylanase was high up to 1550.62 U /g and 1545.38 U /g, respectively.