Abstract: Edible fungi obtain nutrition by decomposing mycelium through the secreting extracellular enzymes. This paper reviews the main classifications of extracellular enzymes, the basic functions of key enzymes, the classification and nutritional components of mycelium, and the interaction between extracellular enzymes and mycelium. The paper systematically introduces the main extracellular enzyme systems, including cellulase, hemicellulase, lignin-degrading, amylase, pectinase, and protease systems, and analyzes the key enzymes of each system according to their different functions. On the basis of traditional physiological and biochemical research on extracellular enzymes, modern omics technologies have been applied to various aspects of extracellular enzyme-mediated mycelium degradation, and the expression and regulation of key genes have become increasingly clear. The cultivation medium formula for edible fungi is also becoming more diversified, which is conducive to improving the coordination and utilization efficiency between edible fungi species and cultivation medium. The paper also provides prospects for optimizing the cultivation medium formula and artificially regulating extracellular enzyme production, in order to promote the development of the edible fungi industry.