Oasis is one special geographical landscape produced and developed by rivers in arid area, and in which natural power and human power play important roles together in ecological evolution. Although its dimension is 4%--5% of total arid area dimension, more than 90% population and 95% wealth of the arid area gathers in oases. Oasis is not only quintessence of the arid area, but also the most important activity spot in which people exploited resources and developed production and so on. Then oasis sustainable...