Cordyceps militaris, a kind of caterpillar fungus, has therapeutic effects including immunoregulative, anticancer, antibacterial and antifungal effects. Aqueous extraction and alkaline (NaOH) hydrolysis method were comparatively studied in polysaccharides extraction from submerged-cultured C. militaris mycelia. The results indicate that the polysaccharide content and the total extract rate from alkaline extraction method were obviously higher than those from the aqueous extraction method. The extraction process parameters of alkaline extraction were further optimized using response surface met...