Soil water, as a major factor limiting vegetation in deserts, does not only affect the survival and growth of plants, but also the species abundance and distribution. To research the spatiotemporal variations of soil moisture content in root zone is vital for understanding the recovery, maintenance and the stability of plant communities in deserts. In the Gurbantunggut desert in northwestern China, Haloxylon ammodendron as the dominant species plays an important role in dune stabilization. However, little is known about the effects of plant life stage on the variations of soil moisture content in the root zone for Haloxylon ammodendron. In our study, soil water dynamics were monitored for eight typical Haloxylon ammodendrons individuals in an inter-dune low land at the southern edge of Gurbantunggut Desert, each with a soil moisture monitoring point 20-30 cm away from the stem base. Another two points were set in the inter-shrub bare soil. In addition, 16 points were positioned two individuals with 10 meters away from each other. Thus there were totally 26 points. From February 2014 to November 2014, in-situ observations for soil moisture within 0-400 cm soil were performed by neutron probe method in combination with oven-drying method to explore the spatiotemporal variations of soil moisture in the root zone of Haloxylon ammodendron individuals at different life stages. Results show that (1) the annual variation of soil water underwent 4 periods, i.e., recharging period (from later February to early March), equilibrium period (from early April to late May), discharging period (from early June to late October), and stable period (from early November to middle February of the following year); (2) soil water dynamics differed within profiles, with a higher coefficient of variation that decreases rapidly with depth in the top 50 cm soil layer, and a relatively constant coefficient for 50-400 cm soil layers; (3) the averaged soil moisture content at different life stages in spring, summer, fall, as well as in the whole year displayed a pattern in order of dead individual > adult individulal > young individual > bare soil; (4) soil moisture decreased gradually with the increasing distance to the Haloxylon ammodendron base stem within 5 meters; and (5) following rainfall events, the soil moisture content in 10 cm soil increased more in the root zone than in the bare soil.