Glacier is an important component of eco-environment in the source regions of the Yangtze and Yellow rivers.The effects of glacier change on eco-environment has attracted re-searcher's attentions for a long time past in the source regions.GIS provides an efficient tool to analyze the status and change of glaciers.In the paper,the Geladandong area in the source region of the Yangtze River and A'nyêmaqên Mountains in the source region of the Yellow River are selected as the test areas.Based on RS data in the two periods-one in1969and the other in2000in Geladan dong area of the source region of the Yangtze River,one in1966and the other in2000in A'nyêmaqên Mountains of the source region of the Yellow River,glacier variations during the Little Ice Age(LIA)maximum,in1969(1966)and2000are analyzed by means of aerial photos,satellite images,topographic maps and the derived digital elevation models (DEM).Glacier changes in the whole source regions of the Yangtze and Yellow rivers are inferred from study of the above two test areas.Tuotuohe basin is selected as typical area.The impacts of glacier variations on surface runoff are analyzed in Tuotuohe basin in the paper.The results indi-cate that the glacier area had decreased by about 1.7%from1969to2000in Geladandong area of the source region of the Yangtze River,while about 17%from1966to2000in A'nyêmaqên Mountains of the source region of the Yellow River,and that the largest retreat rate of glacier terminus is41.5m per year in the Geladandong area,while57.4m per year in A'nyêmaqên Mountains.Compared with glaciers in the source region of the Yellow River,withdrawal rate of glaciers is smaller and glaciers seem almost steady in the source region of the Yangtze River.Glaciers advance markedly from1969to1995in the source region of the Yangtze River and from1966to1981in the source region of the Yellow River.At this period the majority of glaciers is in advance or stable state.The changing time from glacier advance into retreat in the source region of the Yangtze River is about 10years later than that in the source region of the Yellow river.Glacier retreat results in about 7million cubic meters losses of glacier causes water resources every year in the source regions of the Yangtze and Yellow rivers,respectively.Although retreat of glaciers causes increase in glacier melt water runoff,the effect of glacier retreat on sur -face runoff is relatively small because of small ampli tude of glacier change.