Abstract: Taking the Poria cocos as raw materials, this paper developed the optimization of alkali soluble polysaccharide extraction technology, compared the content and structure of polysaccharide in Poria cocos sclerotium and its processing leftover, used the ultramicro smashing method to deal with the polysaccharide and the Poria cocos powder, and compared the change of physical and chemical nature with the native samples.The results showed that the optimized extraction of alkali polysaccharide is as follows: treatment temperature 4℃, concentration of alkali 0.75mol/L, extraction time 8h and the ratio of stuff to alkali solution 1:40, that the polysaccharide content of Poria cocos sclerotium is higher than the Poria cocos processing leftover which could also be a good origin material of polysascharide, and that compared with the native samples, the physical and chemical nature of the ultramicro smashing samples has certain change, which can be better used as food processing stuff.

Key words: Poria cocos sclerotium, Poria cocos processing leftover material, alkali polysaccharide in Poria cocos ultramicro smashing method