【英文摘要】The hypogeous fungi are one of the most important group of fungi in natural ecosystem, but less known by most of people of its very special inhabitation that the truffle-like fruiting bodies are produced underground generally, and very different from those epigeous fungi. Recently, the group of fungi have been better studied in some countries, as in USA, Australia, UK, Spania and so on. The basic reseach focuses mainly on taxonomy for species, with the geographical distribution and ecological characteristics of hypogeous fungi in Xizang, to determine the systematics among them in biology, the interactions in ecology, and to recognize the functions in plateau ecosystems, especially in plateau forest ecosystems. In the past three years, more than 500 specimen including some very special species were collected in Xizang, and over 70 species (including new species) are identified up to now, belong to 7 orders, 16 families and 21 genera except 1 species of anamorphic fungus. The field work reveals the hypogeous mycoflora of Xizang is similar to the North American and European mycoflora, while almost none relationship with the southern hemisphere mycoflora. In Xizang, some hypogeous species may distribut to over alt. 4600m that is not documented previously, and most of hypogeous fungi occur in oak forest and fir forest, number of species and output occuring in the later Autumn are more than in the other seasons. In this studies, that the fruiting bodies of some species in Xizang are produced above ground and exposed completely where underground or embed deeply in other regions or countries are discoved, and that some ascocarps of a hypogeous fungus may form ectomycorrhizae with herb (a kind of fern) is proved. After analyzing and comparing, The Mountain Namjabarwa and its adjacent areas is a key area of diversity and evolution of hypogeous fungi in Xizang. The research results have great scientifical significance for enriching the fungal biodiversity of China and even the globe.