Abstract: The aim is to explore the optimum extraction conditions of Stropharia rugosoannulata polysaccharide by alkaline method and provide references for S.rugosoannulata polysaccharide utilization. The 100 orders powder of S.rugosoannulata was prepared for polysaccharide extraction. The orthogonal test of the single factor or four factors including alkaline concentration (pH), solid to liquid ratio (mL/g) , temperature (℃) and extraction time (min) on three levels was used to determine the optimum extraction method. The yield of polysaccharide was calculated by phenol-sulfuric method. The results showed that the extraction yield of polysaccharide was affected in order by pH, time, temperature and solid to liquid ratio. The best condition to extract polysaccharide was: pH 9, 50 min of extraction time, 70℃, and 60 mL/g of solid to liquid ratio. The extraction yield of polysaccharides of S. rugosoannulata reached 8.12%. This means alkaline method is preferable to extract S. rugosoannulata polysaccharide. At the same time, such extraction process is simple, stable and feasible in S. rugosoannulata polysaccharide extraction.