Glacier meltwaters are an important component of surface water resources in western China. Based on glacier inventories, the total glacier area in China is 5.87 x 104km2, the second largest for an Asian country. The total storage of water in glaciers is about 5132 x 103 km3, and the mean annual amount of glacier melt runoff is about 5.64 x 1010m3, o r 2% of the total surface water resources of China. From the late 1950s to the present, measurements have been undertaken of about twenty mountain glaciers, and data on hydrology and meteorology obtained. The relationship between heat balance and glacier ablation has been investigated but for glacierized areas where there are no data, ice-melt runoff can be estimated from climatic data. Runoff of glacier meltwater decreases with increasing aridity of the climate. The impact of glacier meltwater on the regimes of mountain streams in different environments are described in this paper.