Abstract: The oasis Population, Resource, Environment and Development (PRED) system has the same character as the other regional PRED system, it is a nonlinear complicated huge system, also it is distinctive characteristic by big expanding spatiality, high frequency of natural disaster, and rich in illumination and heat quantity resources , and so on. But it is a very fragility ecosystem. By using the method of analytic hierarchy process (AHP method), the front 3 factors among 25 factors for the sustainable development of oasis PRED system are per capita water resources(weighting value 0.124), area of dedesertification(0.077), education degree of population(0.062). The comprehensive states and potential of society, economy, population, resources and environment of 20 counties(or city, district) in Hexi corridor were calculated and analyzed by the sustainable development index, and expressed by a map visually, the spatial distribution characteristics are described according to the sustainable development index (SDI) and the map. The front 4 counties were Mongolian Autonomous County of Subei (SDI=0.437), Jiayuguan City and Yumen City (SDI=0.406), Jinchuan District (SDI=0.405). Sustainable using of water resource is the basis for the social and economic sustainable development. Per capita water resources quantity of Mongolian Autonomous County of Subei is maximum in 20 counties. At the back 3 counties were Gulang County (SDI=0.150), Minqin County (SDI=0.213), Tibetan Autonomous County of Tianzhu (SDI=0.217). For the sustainable development of oasis, the optimum ratio among agriculture, industry, and the third estate (service trades, tourist trade, information etc.) is very importance, the causes are analyzed and some answers to the question are given.