Abstract: Population and cultivated lands are the key sub-systems of artificial oasis system in arid areas. Their levels of development reflect the state of artificial oases. The state of the artificial oasis system in Tarim River Mainstream Area (TRMA) largely influences sustainable development of the entire Tarim region. Per-cultivated land production, which composes of food, cotton and other economic crops, was used to estimate land production in the region in this paper. Next, the factors that affect total cultivated land production in TRMA were measured. Food population carrying capacity and cultivated land pressure indices were used to assess the level of development of artificial oasis system in TRMA. Studies show that irrational human activities in the lower reaches of Tarim River heavily influence sustainable development of oasis system in TRMA during 1988~2007. Rapid increases in population and cultivated lands, irrational planting structures, unsafe food problems and mounting pressure on cultivated lands are the determinant factors of oasis systems in TRMA. More attention should therefore be given not only to rational cultivated land utility in the upper and middle reaches of TRMA, but also to population growth and rational development of cultivated land in the lower reaches of TRMA. It is essential to control population and cultivated land growth strictly in the lower reaches of TRMA for the sustainable development of TRMA. And the optimizing pattern of sustainable product is to develop cotton plant mainly and give consideration to crop product on the base of crop safety in TRMA.