The changing features of groundwater resources in recent 50years have been anal-ysed and compared by using calculated results based on surface water from mountain area s and their corresponding groundwater balance during different period of time in Hexi Corridor.The result shows that the annual surface water resources from mountains are relative stable,mean-while the recharges of groundwater are decreasing successively because of industrial and agri-cultural development and ir rigation system in the middle reaches becoming better and approach-ing perfection day by day since the1950s.The groundwater recharge decreased from62.413×10 8 m 3 in1955to55.514×10 8 m 3 in1999.As a result,a se ries of hydrogeological problems,such as constant decline of regional groundwater level,substantial reduce of spring water,yearly en-largement both in scale and amount of groundwater extraction,continuous decrease of surface water entering into the lower reaches,water quality worsening and so on.The eco-environmental system tends to change and becomes deteriorated with the changes of water resources in utiliza-tion and distribution patterns.