The temporal-spatial variability of soil moisture content on a hillslope in a humid area was analyzed based on field monitoring data. Hourly data over a year were collected with frequency domain reflectometry(FDR)sensors. Twenty-four sensors near the soil surface and 12 sensors in two profiles were set up to monitor the soil moisture content continuously. The coefficient of variation and semi-variogram were used to analyze the soil moisture content’s temporal variability in different locations and the spatial variability in different seasons in the study area. The results show that, in the Taihu Basin, the surface soil moisture content exhibited a medium or low level of variability. Soil characteristics, topography, vegetation, meteorological factors, and human activities influenced the temporal-spatial variability of soil moisture. These factors had different effects on the temporal-spatial variability, and the dominant factors were different in each of the four seasons. The semi-variograms for the soil moisture contents in different seasons had similar patterns due to different effects of the factors.