Abstract: The space-time variety Characteristics of soil moisture content are studied on mobile dune in Liaoning Northwest Sandy land. The results show that soil moisture varied with rain Soil moisture content is 0.1%~3.1% in springtime, which is lower. Soil moisture content is 2.5%~5.1% in summer, which is higher. Soil moisture content in autumn is higher slightly than springtime, being2.2%~3.6%.The variation of soil moisture content is bigger at the depth of 0~10cm and effected on rainfall and evaporation intensively, smaller comparatively at the depth of 10~80cm, stable at the depth of 80~120cm.Soil moisture content of different locations on mobile dune is significantly effected on frequent thickness varieties of dry sand layer and rainfall, showing shady slope bottom＞sunny slope bottom＞sunny slope middle＞top＞shady slope bottom.