Abstract: Clarifying the spatial-temporal variation characteristics of soil salinization is the basis for ensuring precision irrigation and crop growth in arid cotton fields. Considering different irrigation nodes and modes in cotton fields, apparent electrical conductivity was measured and soil samples were collected three times during the growth period of cotton by using the electromagnetic senser (EM38-MK2). The inversion model between apparent electrical conductivity and measured electrical conductivity was constructed. The spatial-temporal variation characteristics of surface soil salinization were analyzed by using classical statistical methods and geostatistical methods. The results showed that the local model established by the apparent electrical conductivity and the measured electrical conductivity had a good accuracy with a R² greater than 0.79, which was superior to the global model with a R² only 0.52, indicating that the local model is superior to the global model. The surface soil electrical conductivity variability was significantly different in different periods. The coefficient of variation in March and October was less than 50% (a medium variation), while that in July was more than 50% (a strong variation). The optimal semi-variogram models in each period were spherical, and the ratio of sill to nugget value was less than 25%, indicating that the variation of surface salinity was mainly caused by structural factors such as climate, evaporation ratio and groundwater. The salinized soil area in the studied area increased from 0.49% before planting to 98.23% after cotton harvest. During the growth period of cotton, the surface soil was mainly salinized slightly and moderately. The spatial variation intensity of soil salinization was mainly medium, followed by strong. The area occupied by weak variation was the smallest and was mainly concentrated in the middle part of the area, while the strong variation was concentrated in the southern part. This results provided some certain ideas and methods for studying the temporal and spatial variability of soil salinization at the field scale in arid areas.