5.23%。Based on design-expert statistic system, extraction conditions including temperature, time, the ratio of alkaline solution and mycelium, and the volume ratio of alcohol and alkaline solution were optimized for mycelium polysaccharide by center composition design. The results showed that quadratic model was the best model to describe the relationship between the extraction rate of polysaccharide and the factors. R-squared adjusted value of the model was 0.9495, and the simulated coefficient R was 0.9847.By response surface methodology (RSM), we found that when temperature, time, the ratio of alkaline solution and mycelium, and the volume ratio of alcohol and alkaline solution respectively were 73～76℃, 2.6～3.5h, 18.25～25mL/g and 2.5～3.5, the lowest extraction rate of polysaccharide was 4.45%. When temperature, time, the ratio of alkaline solution and mycelium, and the volume ratio of alcohol and alkaline solution separately were 76℃, 3.24h, 23mL/g and 3.5, the extraction rate of polysaccharide would reach 5.23%, a highest value in our investigation extension. 