Abstract:The cryosphere is solid reservoir, and the meltwater of cryosphere affects hydrology, water resource, and water cycles in the watershed, regional, even global scale. The article reviewed on the current research results on the hydrological function, hydrological processes of meltwater and runoff and their effect, the impact on ecosystem and environment of cryosphere from hydrology view. The hydrological function mainly includes the water conservation, runoff supply, and regulation on water resource. The hydrological processes have significantly changed under the background of climate change, the onset of glacier melting period starts earlier and the volume of melting water has increased, and the snow melting period starts earlier, the permafrost degradation has led to winter runoff increasing, which increases the regulation function of watershed runoff. The projected glacier meltwater will continuingly decrease under the future climate change, which will bring greater challenge on the water resource management of Northwest China. The changes in hydrological process of cryosphere also have important impact on the ecosystem and ecological engineering, flood hazard and sustainability, and geopolitics in cold regions.