The soil moisture, which is mainly replenished by rainwater and snowmelt, is a crucial factor in maintaining the stability of the fragile ecosystem. Choosing a typical sand dune as study area in the hinterland of Gurbantonggut desert. In different terrain parts that contain the crest, the slope, and the foot of the natural dune, we laid 7 aluminum tubes by which the soil moisture content could be measured with a neutron probe, disposed 7 plant sample areas, 7 iron poles which mark the wind-sand activity correspondingly, meanwhile, set up one weather station. With neutron probe, through field calibration and systemic study on soil moisture, plant sample area and wind-sand activity. The result shows that the space-time distribution of the soil moisture is closely related to terrain parts, the depth of soil, plant cover, rainfall, and the depth of accumulated snow. It is clear that the space distribution difference of the soil moisture. Generally, the soil moisture content of the inter-dune is higher than the dune crest, the lower slope higher than the upper slope. In the vertical direction, the soil moisture content of the surface layer is highest from late autumn to May of next year, the subsurface layer, from June to July, and the deep layer, after the August. In the time aspect, the change of soil moisture content shows that the soil moisture content is higher and the soil moisture content increases from March to April; the soil moisture content decreases rapidly from May to June; the soil moisture content is least from July to October; the soil moisture content is invariable except the soil moisture content of the surface layer in late autumn and winter.