This study examined typical Nitraria tangutorum nebkha in the UlanBuh desert. An EC-5 soil moisture sensor was used for long-term monitoring of the shallow (0-50 cm) soil water content. We analyzed the responses of different soil layers to different rainfall and soil water content dynamics in a Nitraria tangutorum nebkha during the growing seasons of 2015-2017. The results showed that rainfall was the most important supply source for soil water content. The amount of rainfall was the major factor affecting the depth of water supply in shallow soils. Rainfall < 10 mm was completely absorbed by the surface soil (0-10 cm), and was unable to replenish soil water content below the 10 cm soil layer. Rainfall between 10 and 20 mm replenished soil water content to the 20 cm soil layer; rainfall between 20 and 30 mm replenished soil water content to the 40 cm soil layer; and rainfall > 30 mm replenished soil water content to the 50 cm soil layer. In the case of rainfall < 20 mm, the soil water content of the study area below 20 cm could gradually deteriorate, which could promote the growth of shallow root herbaceous plants, leading to a decline of the Nitraria tangutorum community. Rainfall patterns have an important impact on shallow soil water content and vegetation succession.