Soil moisture data from May to October during 1983 to 1990 at Naiman on Horqin sandy land are applied to study in temporal and spatial variant characteristic ofsoil moisture and effect of precipitation in the different type vegetation. The results showed that the influence of vegetation is significant, soil moisture of shifting sand dune is best, its average value is 3.56% and variation coefficient is 0.074. Second is soil moisture of arbor area which grew in the lower part of sandy dune, its average value is from 2.73% to 3.08%, but soil moisture have not stability, variation coefficient is 0.127 and 0.347, respectively. Soil moisture of semi-bush and bush areas which grew on top of sandy dune are worst, its average values are less that 2.5%, variation coefficient are (0.179) and 0.262, respectively. Soil moisture has also been controled by precipitation,sandy land would appear dried soil layer when vegetation and dry climate influence in the same time, but not in the normal or wet years in the desert region of semi-arid.