The spatial variability of soil moisture is remarkable.Here we used traditional statistics and semivariance analysis of geostatistics to test for differences in the spatial heterogeneity of top soil(0~20 cm) moisture of three different stand age of Salix psammophila in the MU US sandy land.The results showed that there is a tendency towards increasing of the topsoil moisture with the growth of Salix psammophila stand age;the increase range is 5.46% to 6.60%.And all the sampling date of different stand age of Salix psammophila had a significantly(p<0.01) effect on top soil moisture.Semivariogram analysis demonstrated that there is a high spatial heterogeneity in soil moisture.The means of nugget

sill and structural ratio(C/C_0 C) increased with the growth of Salix psammophila stand age.Spatial heterogeneity in top soil moisture was mainly caused by spatial autocorrelation

63% to 87% with the growth of Salix psammophila stand age.There are high levels of variation in pattern in the different stand age of Salix psammophila.The spatial patchiness for top soil(0~20 cm) moisture of 4 years old Salix psammophila is the most fragmented.Because of the increase of spatial heterogeneity

the tendency of top soil moisture is dispersed.