Water Use Efficiency (WUE) is a crucial indicator for a better understanding in the coupling relationship between ecosystem water and carbon cycles. Studies of the spatiotemporal dynamics in ecosystem WUE together with the underlying mechanisms at a regional scale can enhance our ability to evaluate and predict how global change affects the carbon and water cycles. This study reviewd the current research progress on regional ecosystem WUE. The results indicated that: ① Most of the recent researches on ecosystem WUE are at local scale and the regional study is rare; ② There are definite conclusions about the values as well as the temporal dynamics of the WUE across different ecosystems, whereas the spatial distributions of ecosystem WUE obtained by the ecological model needs further verification; ③ Studies proved that climate change and Land Use/Cover Change (LUCC) could significantly alter the ecosystem productivity or evapotranspiration, yet there are quite a few studies on their effects on ecosystem WUE. Hence, the control factors for the spatiotemporal variability of regional ecosystem WUE and its response to climate change and LUCC may be one of the hot issues in the future global change research.