Abstract: To explore the recycling value of defatted Ganoderma lingzhi spore scarp,the extraction technology of crude polysaccharides from defatted Ganoderma lingzhi spore scarp was optimized. On the base of the single factor investigations,the ratio of water to material,the extraction temperature and extraction duration were studied with the Box-Behnken experimental design,and their interactions on the yield of crude polysaccharides from defatted Ganoderma lingzhi spore scarp can be concluded as follows: interactions of time and temperature,temperature and ratio of solvent to material were remarkable,but the interaction of ratio of solvent to material and time was unremarkable. The optimum conditions were the ratio of solvent to material of 25.00 ∶ 1,temperature of100.00 ℃ and time duration of 3.00 h.On these conditions,the yield of crude polysaccharides was up to 13.320%.The actual conditions were the ratio of 25 ∶ 1,temperature of 100 ℃ and time duration of 3 h,and the actual extraction yield was 13.204%. Error between theoretical yield and actual yield was less than 1%. It was maximal extraction yield of crude polysaccharides from defatted Ganoderma lingzhi spoer scarp with optimized process parameters.