Soil moisture is one of the key factors for vegetation restoration and ecological reconstruction on the Chinese Loess Plateau (CLP). To understand the regional spatio-temporal variations of profile soil water content and its potential influencing factors, a south-north transect with 86 observational sites were determined on the CLP. Soil water content was measured using a neutron probe to depth of 5 m from June to November 2013. The distribution and variation characteristics of soil water storage (SWS) were evaluated and simulated using classical statistics. The results showed that SWS within different soil layers exhibited moderate variation and generally decreased from the south to the north of the CLP. The mean SWS within the 0-5 m profile for the transect was 735 mm. Spatial variation in SWS increased with increasing soil depth, while the temporal variation had a decreasing trend, suggesting that soil water content tend to be more temporally stable in deeper layers. Soil moisture was primarily influenced by the aridity, the content of clay, normalized difference vegetation index, and slope gradient on the regional scale. These parameters, therefore, could be used to predict spatial distribution of soil water content at a regional scale in a certain confidence level.