Xinjiang is a typical area in western arid zone in China.Based on strategy of water resource sustainable development,the principle and methodology of water for ecological use are urgently in needed of being resolved.Water for ecological use has several characteristics in arid Xinjiang region.The quality and quantity of water for ecological use have a larger variable range in arid zone.Meanwhile,water use style is flexible and has diversified forms.Water supply has influence on organism productivity.Water for ecological use is under the control of water circulation and transfer efficiency of GSPAC,which has close relation with vegetation characteristics,soil physical and chemical features,and terrain condition as well as water use level.Estimation of water quality for ecological use is based on some parameters and modeling.The ideas of water for ecological use have significances for improving eco-hydrology and water resource management and ecological practice as well as sustainable development of ecological industry in arid zone.