Abstract: Affected by the sand barrier, soil moisture and distribution under canopy of Haloxylon ammodendron Bge have differences. To discuss the distribution law of soil moisture under canopy of Haloxylon ammodendron Bge can improve the survival rate of Haloxylon ammodendron Bge forest and provide theoretical basis for wind prevention and sand fixation. Objects of the study were Haloxylon ammodendron Bge forest having sand barriers with eco-mat, sandbag layout area and bare sand dunes (CK) at Laohukou located in the Minqin Country. 3 representative plants of Haloxylons ammodendron Bge were chosen from sand barriers layout area and bare sand dunes respectively. The samples of soil to 80 cm distance (some soil samples to 60 cm) from the plant in the horizontal of east, west, south and north were taken respectively, every 20 cm as a gradient. The samples of soil to 60 cm in vertical position were taken with every 10 cm as a gradient, and the indexes of soil water were measured. The results showed that: soil moisture under canopy of Haloxylon ammodendron Bge was weakened by the barriers, soil moisture under canopy of Haloxylon ammodendron Bge in CK was greater than that under the two kinds of sand barriers, which had significant difference (P<0.05). But the soil moisture with the two kinds of sand barriers had no significant difference (P>0.05). Moreover, the damage of sandbag weakened the soil moisture of Haloxylon ammodendron Bge within sand barriers. The roots soil covered with eco-mat barriers had rich water content, but the water moisture became less with the increase of the distance.