Either climate is dry and precipitation is little or evaporationis intense, the ecological environment is quite fragile. The natural disasters, such as, drough t in spring, flooding in summer, salinization and blowing sand, are ubiquitously in existence in the Tarim Basin. Water resource utilization and ecological envi ronment issues have been given rise to widely attention in the Tarim Basin. Acco rding to the study on groundwater and soil moisture as well as the relations be t ween vegetation growth and ecological environment quality, rational ecological w ater level is delimitated. Based on vegetation water consumption and quota estim ation, the ecological water demand amount in four sources including Tarim River Basin, Yekat River Basin, Hetian River Basin and Kaidu-Kongque River Basin a re 16.18×108m3,14.796×108m3,7.985 3×108m3 and 10.499 8×108m3,respectively. The ecological water demand amount in the main stream in 20 05,2010 and 2030 are 31.859×108m3,36.272 3×108m3 and 41.035 5×108m3, respectively. Under proceeding of China accelerating development in west e rn regions, to approach the theory and pattern for ecological sustainable develo pment in the Tarim Basin, it has great significance in social economic develop ment at present and future.