Hulun Lake, the largest freshwater lake in the Eurasian steppe, is a critically climate-sensitive water body facing severe ecological threats. This systematic review synthesizes multidisciplinary evidence from 1961 to 2025 to examine the characteristics and drivers of its water environment and quality evolution. The findings reveal that the primary driver of the lake's hydrological degradation shifted from natural climate variability to anthropogenic land-use change around 1998. While ecological water diversion has partially alleviated water scarcity, it also introduces a significant external nutrient load, creating a paradox where increased water volume coincides with aggravated eutrophication. Furthermore, overgrazing in the catchment not only enhances conventional runoff pollution but also facilitates a unique "tumbleweed-mediated cross-media pollution" pathway. This review concludes that the restoration of Hulun Lake necessitates a shift from singular water quantity regulation to an integrated management strategy that concurrently addresses water quantity, quality, and aquatic ecosystem health. The insights gained are crucial for informing the sustainable management of Hulun Lake and other inland lakes in cold, arid regions under global change.