Soil moisture is a key factor for plant growth and eco-environment restoration on the Loess Plateau, China. The Loess Plateau is has an arid and semi-arid climate, complicated landforms, and a unique loess-deposition soil environment. The understanding of zonal pattern in soil moisture under different land use types is fundamental for environmental mnagement for the selection and plantation of non-native vegetation types. In the present study, a transect with an area of 194000 km² was selected at the center of the Loess Plateau with a north-south direction to investigate the effects of the changes in rainfall, potential evaporation, soil texture, and vegetation types on soil moisture. This transect included all vegetation, soil, and climatic types of the Loess Plateau. Soil moisture profiles of 0-500 cm under farmland, grassland, shrub land and woodland were measured using the sampling method in 29 counties from the southern to northern Loess Plateau from July to August 2014. Soil texture, vegetation, slope, slope direction, elevation, latitudes, and longitudes were also measured. The results showed that: 1) soil moisture under four land use types decreased gradually from the southern to the northern Loess Plateau with increasing latitude. This corresponded to the distribution of the mean annual precipitation, potential evapotranspiration, and soil clay texture across the Loess Plateau; 2) soil moisture was significantly different under different land use types through the comparison of soil moisture in horizontal and vertical directions. The general trend for the soil moisture was: farmland > grassland > shrub land > woodland. The differences in root distribution and evapotranspiration under different land use types resulted in the above trend; 3) six factors, including mean annual precipitation, latitude, clay content, sand content, silt content, and potential evaporation, were identified as the main factors affecting the soil moisture content determined by correlation analysis. The mean annual precipitation and clay content were identified as the most important factors influencing soil moisture using stepwise regression analysis. Compared with the clay content, the mean annual precipitation was the main factor determining the spatial variation in soil moisture under different land use types. This information is useful for environmental managers to ensure ecological restoration on the Loess Plateau.