Water resources system in northwest inland river basin is affected by various kinds of water supply, therefore, its evolution demonstrates complexity and susceptiveness to climate change. Besides, the special geographical location contributes to its unique evolution process and clearer non-stationary feature and vulnerability. Comprehensive effect of multiple driving force factors, consequently, increase the management of risk and uncertainty of Tarim basin water resources. Based on hydrological and meteorological data during the period 1962-1997 from those hydrologic stations and watershed meteorological stations in terms of the three rivers originated from the Tarim River basin and the snow-cover material during the period of 2000 to 2011, multiple COPULA joint distribution model between the meteorological, hydrological variables is established in the paper. Evolution driving force of water resources system in different periods and its dependent measure change are analyzed according to the dependent structure change point detection and tail correlation results. Meanwhile, Analysis of the risk probability of the natural runoffs of the main tributaries and further discussion of the space-time change of river basin water resources evolution are made to provide a reliable basis for regional water resources management.