Climate change has a considerable impact on the productivity and water use of terrestrial ecosystems. Water use efficiency (WUE) is an important indicator to measure the tradeoff between carbon gain and water loss of terrestrial ecosystems. Studying the responses of terrestrial ecosystem WUE to climate change will help us understand the mechanism of ecosystem changes, simulate and predict the development of the ecosystem water and carbon balance, and provide a new basis for adapting to global climate change. To better understand the status of ecosystem WUE and the responses of WUE to key climate factors, such as temperature and CO₂ concentration, this study reviewed the current status and progress of the responses of terrestrial ecosystem WUE to climate change. Firstly, definitions of WUE were introduced and the differences as well as characteristics of two WUE calculation methods were summarized. Then, the responses of terrestrial ecosystem WUE to climate factors, such as temperature, CO₂ concentration, humidity, drought stress, and radiance, were elaborated. Finally, the three current research directions of WUE development were forecasted, mainly including:① the relationships between the long-term WUE and climate factors; ② the impact of land-use and land-cover change on WUE and its feedback on climate; and ③ comprehensive research of multi-scale WUE. This study can provide a reference for studying the responses of terrestrial ecosystems to climate change.