Ergosterol chemical name 24β-methylcholesterol-5,7en-3β-hydroxyl group, also known as ergosterol, is white or colorless bright leaflet crystal or white crystalline powder. Ergosterol not only has unique physiological effects, but also is widely used in the development of pharmaceutical chemicals. As an important component of fungal cell membranes, ergosterol has stable structure and strong specificity, which is more representative than glucosamine for the determination of biomass, so the biomass of fungi can be measured by detecting the content of ergosterol.