The Hexi Corridor, an important part of the Silk Road Economic Belt, is considered the poorest, most water scarce, and most ecologically fragile area in China. Establishing efficient strategies for water management in an integrated manner is utterly important. This paper evaluates the spatio-temporal trends of water stress (2003–2015) in the Shule (SLRB), Heihe (HHRB), and Shiyang (SYRB) River Basins in the Hexi Corridor based on the Water Poverty Index (WPI). For SLRB, the WPI ranged from 55.3 to 66.4, followed by HHRB (40.1–58.2) and SYRB with WPI = 20.0–43.9. Both SYRB and HHRB showed an improvement in the water situation based on increasing trends, whereas SLRB demonstrated a small decrease. The effectiveness of water policy interventions was evident in SYRB and HHRB, standing at odds with SLRB where interventions required adjustment to ameliorate the water stress. For the start and end years, pentagrams for five components (Resource, Access, Capacity, Use, Environment) demonstrated the merits and weaknesses of WPI as a comparative framework for assessing the water situation. This study also reaffirms the importance of WPI, utilized for investigating the efficacy of implemented water policies and benchmarking the future priorities in basins not only in China but also in other locations where water resources management is a key issue.