Abstract: The water use efficiency of dryland was low in southern Ningxia. The experiments were implemented with nutrients abundance and deficiency index method (different combinations of nitrogen, phosphorus and potassium) to study the soil water dynamic distribution of potato‘( Zhuang No.3’), potato yield components, yield and variation characteristics of water use efficiency. The effect of different fertilization treatments such as CK, NP, NP, PK and NPK on soil cross-section dynamic water storage, potato yield and water use efficiency was discussed. The results showed that in 2011 and 2013, soil profile moisture contents of fertilization treatments were all lower than that of the control in the late growth period, and NK and NPK treatment improved 1 m soil water content in the tuber growth period (by 1.1% and 3.2% respectively), and increased the potato water consumption (by 1.8% and 4.4% respectively). Compared with the control, NK and NPK treatment raised potato yield by increasing the number of tubers and grain yield per plant (NPK treatment had the highest yield, the increase rate of the number of tubers was 11.7% and that of the grain yield per plant was 15.9%, and the yield of NK treatment was the second). Compared with the control, water use efficiency of NPK treatment increased by 2.9% to 13.2%, while that of NK treatment increased by 2.8% to 8.0%. Potato yield and water use efficiency in dryland of southern Ningxia were significantly affected by the lack of nitrogen and potassium. Nitrogen cooperated with potassium fertilizer and the reasonable application of NPK fertilizer could improve the ability of soil water utilization in potato, therefore, to increase the potato yield and water use efficiency.