Because of shortage of rainfall and drought during the growth period of winter wheat in northern China,the available soil water(ASW)formed in flood season before planting,parti-cularly water stored in deep soil layer has become one of the important water sources for winter wheat growth.The experiments were conducted in man-controlled water supply field at Gucheng Agrometeorological Experimental Base of China Meteorological Administration(CMA).Two ferti-lizing depth treatments and a contrast(CK)were applied:(1)fertilizing at0～20cm(C1),and(2)fertilizing at20～40cm(C2).We analyzed the effect of different fertilizing depths on the growth of root system,the use of the available soil water before planting,water use efficiency and winter wheat yield.The experimental results indicated:the fertilizing depth of20～40cm can strengthen the growth of root system in mid-layer and deep-layer,therefore the space where wheat may ab-sorb more water and nutrient can be extended.This contributes to effective use of water in deep soil layer,which can bring into play the regulation function of soil reservoir to improve water use efficiency and yield of winter wheat.