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.