A field experiment was conducted to study effects of root pruning at returning green stage on popu- lation structure,soil water and yield formation of winter wheat.The results showed that root pruning treat- ments reduced population density and improved population structure of wheat,which resulted in higher PAR penetration rates compared with the control.Root pruning reduced water consumption of wheat in the early growing stage,so root pruning plots had higher soil water content than the controls at anthesis,which pro- moted physiological activity and resulted in higher photosynthesis rate in root pruned wheat compared with the control.Light root pruning did not affected grain yield,but increased water use efficiency for grain yield~ heavy root pruning improved water use efficiency for grain yield,but cut down grain yield greatly due to di- minished spike number compared with the control.Our study showed that it is very important that suitable agricultural measures to improving yield and water use efficiency(WUE) of wheat,by which more soil water was saved and supplied to plants after anthesis by reducing water consumption in the early growing stage, should be explored and brought in practice in arid and semi-arid areas.