Abstract: Groundwater is an important water source for sustaining the survival of mankind, the ecological health and socio-economic development in northwest inland, China. However, the local ecosystem is fragile in those regions. To protect groundwater resources and ecosystem, it needs to  study the rational development and utilization of groundwater. Base on the analysis of hydrogeological feature and environmental problems, the paper clarified the groundwater ecological function and its threshold using remote sensing technology, field survey and groundwater monitor approach in Golmud River catchment, Qinghai Province, China. The results showed that the reasonable groundwater depth should be in the range from 0.5 to 10 m for the survival of plants, and lager than 3 m for alleviation of salty soil. To prevent the city from waterlogging, the ground reservoir should larger than 3.42×108m3. And it also needs more than 2.82×108 m³ water volume flowing into the lake per year to maintain Dabuxu Lake area. According to the ecosystem services economic contributions, it found that the profit would be 80 million yuan and 1.63 million yuan per square kilometer for the city waterlogging prevention and salty soil alleviation, respectively. On the contrary, the loss would be 1.91 million yuan per square kilometer and 10.32 million yuan per square kilometer because of vegetation degeneration and lake area shrinkage. The research results provided useful information to support groundwater sustainable use and ecosystem protection for Golmud River catchment. Meanwhile, it can be used as reference for groundwater utilization in other catchments in northern China. 

Key words: groundwater ecological function, environment profit, Golmud River catchment