Abstract: The sandy soil positioning research method was used to study the soil water characteristics and the variation of water potential in SPAC were systematically studied in Maowusu sandy Land. The results were as follows:(1)the empirical equation θ=AS-B could well simulate the water characteristic curves of the soil.The study also showed that the soil had the low moisture capacity and the less supply water and low drought endurance.(2)The main resistance of water distribution in SPAC was from leaf to atmosphere,the distinctly seasonal change of soil moisture was the common result of rainfall,evaporation from the forest floor and transpiration of the trees,the tree tested had a clear daily variation in leaf potential,under the condition of drought stress,the lowest leaf potential appeared in advance,leaf water potential had a correlation with soil and atmosphere water potential to a certain extent.