Mushroom proteins with physiological functionality could be classified into agglutinins with activity of cell agglutination, ribosome inactivating proteins and polysaccharide-protein complex according to their biochemical characteristics and physiological activity. Mushroom agglutinins with molecular weights ranged from 12 to 190 kDa are composed of 1 to 5 subunits. The agglutinins are categorized into lectins, fungal immunomodulatory proteins and agglutinative glycoproteins, with respect to their specific affinities against various carbohydrates. Mushroom proteins might be implicated in the regulation of fungal metabolism and symbiotic, or parasitic relationships with other organisms. Anti-tumor activities of mushroom proteins may be resulted from the stimulation to the immunity of the host. The proteins of Ganoderma lucidum, Flammulina velutipes, Volvariella volvace, Agaricus bisporus and Tricholoma mongolicum might be applied in clinical medicine.