With the socioeconomic development and continuous increasing of population, the water resources shortage is increasingly serious in recent years and that in arid and semi-arid regions of Xinjiang is even more serious. Principal component analysis method is used to horizontally compare and analyze carrying capacity of water resources in all prefectures (municipalities) in Xinjiang from the perspective of spatial dimension in accordance with economic development and conditions of water resources of all prefectures (municipalities) in Xinjiang in 2010. The study result shows that the carrying capacity of water resources in Xinjiang shows drastic difference in space. Comprehensive score of 5 regions in South Xinjiang is high on the whole, indicating that natural conditions such as natural endowment of water resources in arid and semi-arid regions of Xinjiang have great impact on the carrying capacity of water resources.