Abstract: The reality is that there today exists not only an increasing scarcity of water resources, but also worsening ecology of the Qitai Oasis in Xinjiang. It is thus urgent to build an index system of water resources carrying capacity. So, in this paper, principal component and entropy analyses were used to select and empower the main indexes of water resources carrying capacity in the oasis region. Water resources carrying capacity of Qitai Oasis was analyzed and evaluated to facilitate not only rational use of water resources in the oasis region but also sustainable development of the oasis ecology. The results showed that water resources carrying capacity in the oasis region was 0.83 and 0.75 in 1993 and 1998, respectively. It dropped to the lowest value of 0.66 in 2005. The trend of decline in water resources carrying capacity accelerated with time. The rate of decline in 2003 to 2005 was 47.96 times as much as that in 1993 to 1998 and 8.93 times that in 1999 to 2002. Qitai Oasis water resources carrying capacity was mainly driven by five main factors, including economic and ecological factor, population factor, agricultural water use factor, climatic factor, and other water uses factor. The accumulated contribution rate of the three former factors was 73.58%. This was a solid reflection of the negative effects of rapid economic development, increasing population and agricultural irrigation, and worsening ecological environment on the availability of water resources and the increasing potential for further water saving in the oasis region.