Abstract: High-altitude cold regions are susceptible to global warming, experiencing rapid changes in glaciers, snow cover, permafrost, and vegetation. This paper systematically reviews research progress over the past two decades on the evolution and simulation of hydrological processes in these high-altitude cold regions. The review indicates that: Climate warming drives synergistic changes in the cryosphere and vegetation, accelerating glacier melt, shortening snow cover duration, degrading permafrost, and enhancing surface-groundwater connectivity. Vegetation greening and shrub expansion exert complex influences on the water cycle by altering snow accumulation, evapotranspiration, and permafrost conditions; Hydrological regimes are profoundly reshaped, with snowmelt runoff peaks generally occurring earlier, permafrost thaw raising baseflow during dry seasons, significant spatial variations in total runoff, and endorheic basin lakes expanding under the dominance of net precipitation; Hydrological models are evolving towards multi-sphere, energy-water coupled frameworks, though bottlenecks remain in representing permafrost-groundwater interactions and vegetation-hydrology coupling mechanisms. Future research should prioritize breakthroughs in the following areas: ① Climate change and cryosphere response: Establishing a multi-sphere synergistic observation system, deepening the understanding of regional heterogeneity mechanisms, and strengthening the assessment of critical thresholds. ② Hydrological regime changes: Constructing a comprehensive hydro-eco-social assessment framework for high-altitude regions and establishing an early warning system for extreme events. ③ Hydrological process modeling: Deepening the parameterization of hydrothermal coupling in permafrost, improving the representation of multi-sphere energy-water coupling, and developing multi-scale dynamic simulation capabilities.