Abstract: Through a long-term located experiment,the crop yields and water use efficiencies under different water and fertilizer conditions in the field of black soil were studied.The results indicate that the yield of soybean more relies on the water conditions,but the corn yield more relies on the fertility.The yields and water use efficiencies of spring wheat,maize,and soybean increase along with more fertilizer under reasonable water conditions;and they also increase as soil water content goes up under manure and organic conditions.