[Objective] By analyzing the changes of soil water content beneath the canopy of rain-fed Haloxylon ammodendron forest in which sand barriers were established

this paper aimed to provide theoretical basis for evaluating the ecological functions of sand barriers as well as forecasting the growth and development situation of the Haloxylon ammodendron forest. [Methods] Two sites of 5 and 25 years old Haloxylon ammodendron forests were selected to establish wheat straw and plastic net sand barriers. Wherein

soil water contents of 0-50 cm depth

crust thickness

near-surface wind speed beneath the canopy were measured and analyzed. [Results] Under the influence of sand barriers

soil water contents of 0-50 cm increased

air flow velocity in near-surface decreased and the formation of crust was speeded up. The sand barriers had no significant influence on the spatial distributional pattern of soil water contents beneath the 5 years old Haloxylon ammodendron canopy. Whereas

"dry island effect" was observed for the 25 years old Haloxylon ammodendron canopy

i.e.

soil water contents decreased monotonically with the distance decreasing from the tree trunk. Soil water content in the vertical profile between plastic net sand barriers area and contrast area had a significant correlation(p<0.05)

while had no evident correlation between wheat straw sand barriers area and contrast area. The depth with biggest soil water content in wheat straw sand barriers area descended to 30-40 cm. [Conclusion] Establishment of sand barriers had somewhat acceleration effects on the recovery of degenerated Haloxylon ammodendron forest

it was more obvious for the middle age forest than the young forest with regard to the effect on soil water.