The influences of soil factors on arbuscualr mycorrhizal fungi (AMF) were investigated in central Tibet altiplano pasture. The results showed that there were no corelation between the spore density which was defined as spore number per gram soil with mycorrhizal colonization; the effect of soil texture on AMF spore density is greatly larger than that of soil type. Mycorrhizal colonization in loam or silt were higher than that in sandy sandy soil. Soil pH showed significant correlationship with spore density, while soil organic matter content showed sig- nificant negative correlation. Mycorrhizal colonization was increased with increasing of soil oaganic matter con- tent, but decreased with increasing of soil Olsen-P content. It was also noticed that AMF well colonized cyper- aceae plants, such as Kobresia humilis and Cyperus compressus.