The extraction and purification methods of polysaccharides from edible fungi determine their structure, which in turn affects their biological activity, and is the basis of research on edible fungi polysaccharides. Some specific structural features make the biological activity of edible mushroom polysaccharides significantly enhanced. Therefore, researchers have used physical, biological and chemical methods to modify the molecular structure of edible mushroom polysaccharides to improve their biological activity. The review introduced the extraction, purification and structural modification methods of edible fungi polysaccharides. The advantages and disadvantages of extraction, purification of polysaccharides from edible fungi, and the effects of chemical modification on their structure and biological activity were summarized. The importance of appropriate extraction and purification methods for obtaining the target polysaccharides and the importance of chemical modification methods for changing the molecular structure and improving the functional properties and biological activities of polysaccharides from edible fungi were prospected.