In order to study the temporal and spatial variation characteristics of soil moisture and the correlation between soil moisture content and lake water level in the beach wetlands under changing conditions, the typical continental wetland section of Dongting Lake was taken as the research object, and the water level, atmospheric temperature, and soil moisture content were monitored by in-situ monitoring device for two months. The results indicate that the distribution of moisture field in the wetland of Dongting Lake presents an obvious stratification phenomenon in the vertical direction. The fluctuation range of soil moisture content in the same location gradually decreased with the increase of depth, and became stable in the deep (> 50 cm). The fluctuation range of soil moisture content at the same depth decreased with the increase of distance from the bank. The correlation between soil moisture content and lake water level increased first and then weakened with the increase of depth. There was no significant correlation between the soil moisture content of the shallow and deep layers and the lake water level. The soil moisture content at the depth of 50~70 cm below the surface was highly correlated with the lake water level. The results reveal the interaction mechanism of soil moisture in the underground aquifer-soil-atmosphere interface of the wetland ecosystem, and provide important methods and theoretical references for the study of hydrological processes and ecological environment protection in the wetlands.