Abstract: The quadratic orthogonal rotation design with five factors was used to study the effect of the ratio of material to fluid, temperature, alkali concentration, time and extracting times on the extracting rate of polysaccharides from peanut meal by alkali extraction. The regression equation for the five extracting factors was established by RSREG software in SAS8.1. Results show that the regression equation is significant, and the mathematical model for the simulation is presented. Through the local optimization analysis to the regression equation, it is found that the optimal extracting conditions are as follows: the ratio of fluid to material is 34︰1 (mL/g), alkali solution concentration is 0.68 mol/L, extracting temperature is 88℃, and extracting time is 2.4 h, the yield of polysaccharides is 9.79%