Objective: To optimize liquid fermentative conditions of intracellular polysaccharides from Polyporus umbellatus. Method: Fermentative medium for intracellular polysaccharides in P. umbellatus was prepared by shake flask cultivation.With yield of intracellular polysaccharides from P. umbellatus as index

nitrogen source

carbon source and fermentation conditions were investigated by single factor tests

orthogonal test was adopted to optimize composition of culture medium. Result: The best carbon sources was saccharose

optimum nitrogen source was soybean meal

optimized composition of culture medium was as following:potato 10.0%

saccharose 4.0%

soybean meal 0.3%

KH2PO4 0.2%

MgSO4·7H2O 0.15%;Fermentation conditions were:initial pH 5.2-5.6

shaking speed 180-200 r·min-1

culture temperature 28℃

culture time 7 d. Conclusion: It had advantages in fermentation period and polysaccharide production by liquid fermentation

meanwhile it was important to reduce costs and industrial production of polysaccharides from P. umbellatus.