Abstract: This study researched the impact of nitrogen and phosphorus fertilizer on the dryland soil moisture and root characteristics using a field experiment in the test base of Shanxi Agricultural University in Wenxi. The results showed that, increasing nitrogen rate could improve the soil moisture from turning green stage to heading stage and root activity, total root length, total root volume, total root area and total projected area of different stages when the ratio of N and P was 1:0.5 and decreased the soil moisture, root activity, total root length, total root volume, total root area and total projected of different stages when the ratio of N and P was 1: 1. The result also showed that increasing phosphorus rate could improve the soil moisture from turning green stage to heading stage, but decreased it from anthesis to mature stage, and increased the root activity, total root length, total root volume, total root area and total projected area of different stages, and increased the root length, root volume, root area and root projected area of different soil layer from 0 cm to 80 cm, in addition, except the root volume of 60-80 cm soil layer the rest were significant level. In short, the nitrogen rate was 150 kg/hm² or 180 kg/hm² and the ratio of N and P was 1:1, which showed best in the aspect of collaboration of water and fertilizer of dry-land wheat.