Soil microbial response to climate change will affect the whole ecological process,and represent many uncertainties feedback of ecosystem to climate change. Six sample sites and two soil depths (0 - 5 cm,5 - 10 cm), a total of twelve samples were collected along a mean annual precipitation (MAP) gradient in arid and semi-arid, northeastern of Tibetan Plateau and PLFA technology was used to analyze microbial community structure and total microbial biomass. These results showed that total organic carbon and total nitrogen were significantly declined with the MAP decreasing,which was also found in bacteria, fungi,actinomycete biomass. However,microbial biomass had an increased trend in the extreme arid area. Person correlation analysis and Canonical Correspondence Analysis showed that both in 0 - 5 cm and 5 - 10 cm soil depth,MAP had a significant correlation with soil physicochemical properties and soil microbial biomass indicate that MAP was a key factor in soil microbial community structure in arid and semi-arid area,which was more significant in 0 - 5 cm soil depth. The study will provide theoretical basis for further studies of soil microorganisms' response to the water landscape change in the background of global climate change in arid zone.