<p>This monograph can be divided into three parts. The first part is about the classification and morphological characteristics of fungi, which describes in detail the microstructure of Zyomycetes, Ascomycetes (such as Erysiphe graminis), Basidiomycetes (such as Puccinia), and Semiophytes. Taxonomic data of 184 species of fungi in 24 genera such as rust fungi, powdery mildew fungi, and black smut fungi are recorded, including the place where the type specimen was collected and the morphological characteristics of the conidial (such as the toothed processes of the rust telispores and the structure of the powdery mildew accessory filaments). The second part explores the relationship between the ecological distribution of fungi and their hosts. Based on field surveys from 1930 to 1960, it reveals the distribution laws of fungi in ecological areas such as desert grasslands, saline-alkali lands, etc., for example, the dominant bacterial groups in arid areas are Aspergillus and powdery mildew, and different host plants (such as Ephedra and Chenopodiaceae plants) correspond to specific pathogenic fungi (such as Ephedra plants infected with Strickeria sp.). The effects of temperature and precipitation on the spread of fungi were analyzed. The third part is about the pathogenicity and control strategies of fungi. It evaluates the economic impacts of rust causing wheat production reduction by 15%-20%, and the harm of powdery mildew to forage. It proposes biological control (antagonistic microorganisms) and chemical control (sulfur mixture). The combined method also records the antibacterial activity of medicinal fungi (such as Armillaria mellea) and the application value of ecological sand-fixing fungi. </p>