Abstract: This paper presents a field experiment of continuous potato cropping for 1 year, 3 years, 6 years and 10 years with the aim of investigating biological characteristics of potato and dynamic variations in soil water. The experimental results indicate that with increasing year of continuous cropping, potato height, leaf area and net photosynthetic rate decrease. Pre- and post flowering is the water requirement peak of potato. Seasonal variation trends of soil water at different soil layers under different cropping durations are similar, but significantly differ among different cropping year treatments. For different cropping year treatments soils are dry in 40~60 cm soil layer during potato flowering stage, and with increasing year of continuous cropping, soil desiccation is aggravated. Under 6 and 10 years of continuous cropping, soil water content is 11.63% and 10.54% in 50 cm soil layer, gradually developing from light to medium desiccation. For 3 or more years of continuous potato cultivation, WUE decreases drastically. Rainfall in the hilly regions of South Ningxia, where soil layer is usually deep, complements soil water in the upper soil layers. However, deep soil water compensation is hardly realized under potato continuous cropping for more than 3 years. For more 3 years continuous potato cropping, negative ecological and environmental consequences of soil water shortage occur in study area.