The spatio-temporal heterogeneity of soil moisture in Kelan County, Northwestern Shanxi Province was studied in wasteland, Caragana korshinskii forest land and Populus simonii forest land. The soil moisture was determined for the 0-600 cm profile in April, May, June and July. Results showed that:(1) Soil moisture changed between 3.34%~17.19% with irregular variation in the layer of 0-200 cm; However, as the soil depth increased from 200 to 600 cm, the soil moisture of wasteland was increasing, the soil moisture of Caragana korshinskii forest land was decreasing gently and the soil moisture of Populus simonii. forest land decreased at first and then increased gently, respectively.(2) The profile distribution of soil moisture had a significant difference(p<0.01) within different months and different land use types.(3) The variation coefficient of soil moisture was usually in the range of 0~30%, but some individual values are over 50%, suggesting that the structure of soil moisture presented overall stability except special points.