Abstract: Due to the early stage of current work on ground substrate investigation, and with current exploratory stage of multiple sections, the identification of the types and distribution of ground substrate is a basic task in ground substrate investigation work. In this paper, the authors investigated soil ground substrate in the mountainous plain transition area in Eastern Yi County of Hebei Province, and analyzed the spatial heterogeneity of soil ground substrate texture components (sand and clay). The content of the two components is determined to be a moderate variation, by classical statistics and geostatistics methods. The best fitted semi-variogram models are spherical models, which have a moderate degree of spatial autocorrelation within the corresponding range (7 km), thus the most reasonable sampling network size for the study area is determined to be 6.5 km²/point. Kriging interpolation was carried out for the two components to form a distribution pattern map of soil ground substrate in the study area. Based on this model, the characteristics and laws of spatial heterogeneity of soil ground substrate were summarized as follows: Sandy soil ground substrate appeared in areas with low elevation and gentle slope and close to rivers, and ground substrate of clay soil appeared in mountainous areas with high elevations and steep slopes, and away from rivers, affected by topographic factors such as elevation, slope, and distance from rivers. These achievements could provide a research foundation for the deployment and expression of the results in ground substrate survey work.