Based on the experimental results, this paper analyzed the water equilibrium features and ecological adaptability of the dry-land crops in the loess hilly areas of south Ningxia. The results showed that the water satiety rate of whole growth period of summer crops was 55.9%~63.8% in the dry year and 84.1%~86.4% in the rainy year, and that of autumn crops was 67.7%~79.0% and 92.1%~95.1% respectively. The water ecological adaptability varied with the difference of crops and rainfall condition. The water ecological adaptability index (WEAI) of autumn crops was higher than that of summer crops, and the WEAI of crops in the rainy year was higher than that in the dry year. The WEAI of 6 main crops could be put in order as: millet＞potato＞panic＞flax＞pea＞spring wheat. The study results may provide theoretic basis for drawing up the decision scheme of cropping system in dry-land regions.