Abstract: Water use efficiency (WUE) is the basis in water balance research, and the review of spatialtemporal characteristics and drive mechanism of WUE could provide reference for co-ordination management of water supply and demand in different farmlands. The previous study showed that WUE in China had significant spatial-temporal difference, which was generally higher in the north than that in the south and higher in the east than that in the west. In time distribution, WUE in northern farmland showed an increasing trend and that in south China showed a decreasing trend. The precipitation, temperature and radiation indirect affected WUE through the influence on evapotranspiration and total primary productivity, plant structure and genetic factor mainly affected WUE thorough its influence on canopy, root water and carbon exchange capacity, the rational cultivation, irrigation and fertilization could increase WUE of precipitation, decrease the loss of irrigation water, improve the photosynthetic property, and then increase WUE. Considering the spatialtemporal characteristics and variation mechanism of WUE, increasing the water absorption characteristics of crop and reducing irrigation water loss are preferable ways to improve WUE in north China, while coordinating seasonal distribution of precipitation and reducing evapotranspiration and surface runoff are efficient approaches to promote WUE in south China.