The vegetation ecological water requirement has become an essential reference for making reasonable allocation and management of water resources and guiding the ecological construction and vegetation restoration in arid regions. The oasis in middle reaches of Shule River Basin,which is the society,economy and human activity central zone of Shule River Basin,is facing serious ecological and environmental problems and water crisis because of the effects of human activity and climate change. Ensuring the ecological water use is the fundamental measure for protecting the environment. Based on the above-mentioned problems,this paper is aimed at calculating the ecological water requirement of natural vegetation at present and in the future, and provides references for rational allocation of water resource and eco-environmental protection in the study area. Based on the statistical analyses method,remote sensing and GIS technology, and applying the typical phreatic water evaporation model (veriyanov),this paper examined the change in coverage of land use and vegetation coverage in the middle reaches oasis of Shule River Basin, calculated the natural vegetation ecological water requirements of each county, and made prediction of the ecological water requirement in the future according to the key management program of Dunhuang water resources reasonable utilization and ecological protection. The results showed that the ecological water requirement of oasis natural vegetation in the middle reaches of Shule River Basin ranged from 18 768.97* 10~4 m~3 to 46 643.04* 10~4 m~3. Therein, the ecological water requirement of natural forest land was from 1 187.71 * 10~4 to 2 898.72*10~4 m~3,and natural grassland was from 17 581.27*10~4 to 43 744.32*10~4 m~3 in 2013. Ecological water requirement of natural vegetation of Guazhou County, Yumen City, and Dunhuang City in 2013 ranged from 9 685.06*10~4 to 23 392.09* 10~4 m~3,6 552.11 * 10~4 to 17 133.45*10~4m~3,and 2 531.80*10~4 to 6 117.50*10~4 m~3, respectively. It was predicted that the ecological water requirement of natural vegetation in the oasis of middle reaches of Shule River Basin in 2020 would range from 20 655.96 * 10~4 to 66 614.75 * 10~4 m~3,and from 1 316.57*10~4 to 3 855.91*10~4 m~3 of natural forest land, from 19 339.39*10~4 to 62 758.84*10~4 m~3 of natural grassland. The ecological water requirement would range from 22 721.55* 10~4 to 85 584.09* 10~4 m~3 in 2030, and from 1 448.22*10~4 to 4 970.08*10~4 m~3 of natural forest land, from 21 273.33*10~4 to 80 614.01 *10~4 m~3 of natural grassland. The results have important referential significance to promote research on ecological water right, allocation of water quantity, ecological protection, reasonable configuration of water resources and coordinated and sustainable development of eco-society in Shule River Basin. Under the influence of human activities, the study of vegetation water requirement law in different ecological function areas, regional ecological water demand and the threshold should be further strengthened in the future in arid inland river basin.