In accordance with the calculation of water balance equation, the amounts of water consumed in a rainfed wheat field in three experimental seasons were 435.5, 326.0 and 293.8 mm respectively. These results can represent the water consumption under the hydcological condition in excessive, moderate and defective levels respectively in this region. The biomass yield (grain-J-straw) of the wheat was proportional to the water consumption. To take the biomass of the first experimental season a,s the index of 100, the biomass yields of the second and of the third were 85 and 70 respectively. But the response of the grain yield was not identical to the that of tht biomass. They were 100, 102 and 70 respectively in which the highest one was found in the second experimental season. Because the amount of water consumed in this season was relatively low that the water use efficiency was very high (1.73×10^-3kg/l) which was excellent in North China. About 50%; of the total amount of water consumed came froth the water stored in soil before sowing. In the year less in rain fall during the growing season but abundant in water stored in soil, this percentage would be up to 60% showing that soil water is an important water source for wheat growth. lJnder optimum fertilizing conditions, the water use efficiency of wheat was more than 1.26×10^-3kg/1 which was an important parameter for the development of empirical model used to predict wheat yield.