Based on the results of the long term and position research, the soil water content in the sandy soil profiles that covered the Haloxylon ammodendron Bge community and the Alhagi sparsifolia community differ from the soil water content in bare sand profiles. Compared with the former, the soil water content has no obvious horizon variety in bare sand profiles but it is greatly influenced by the precipitation and evaporation. The dynamic of soil water content in the different sandy profiles has obvious seasonal characteristics for the different plant community distribution. It can be divided into three periods, i.e. soil water accumulation (April to May, September), soil water consumption (June to August) and soil water stability (October to the next March). The variable range of soil water content distribution in the slope is obviously because the situation of vegetation cover and soil physical features are different. Compared with the top of slope and middle slope, the bottom of slope has higher soil water content, the maximum is 14.60%.