The composition, structure and functional properties of Agaricus blazei polysaccharide were summarized. The extraction techniques of polysaccharides and the features of different extraction methods were enumerated and compared. The problems in the research of A. blazei was discussed， such as unsystematic basic research, immature technological conditions, imperfect equipment and facilities, and low degree of specificity in seeds. In the end，the research direction of A. blazei polysaccharide was prospected.