Agaricus blazei Murill (ABM) is a type of basidiomycete mushroom with various of nutrition including polysaccharides, ergosterol, sterols, minerals, vitamins, proteins and some phenolic compounds. As a kind of edible mushroom, ABM is also rich in a variety of potential pharmacological applications with administering the extraction contained in its fruiting body or mycelium. On the other hand, even if the ingredients and chemical structures of the ABM have been discovered deeply, the related drug extracted by the Agaricus blazei Murill is rare. This review aims at summarizing the immunoregulation benefits and anti-inflammation advantages of Agaricus blazei Murill polysaccharides (ABMP). With α-glucans and β-glucans as dominant bioactive polysaccharides, ABMP shows evidence in natural killer (NK) cells, macrophages with activating a comprehensive array of signal pathways and protecting creatures from inflammation. Whereas some of the biological mechanisms related to ABMP still remain controversy or conflicts. Furthermore, the experiments about the extractions of ABM may still have limitations in purifying, making some potential mechanisms or reactions unclear and have not been found. Therefore, more data about the ABMP, especially the clinical trials and the further purification of ABMP, is needed to be explored and analyzed.