Abstract: Contour map is the most important method to study the spatial distribution of foundation soil. Nevertheless, the interpolation accuracy of foundation soil was seldom examined by geological investigation drillings. This paper takes the Holocene first marine facies drilling data in Binhai New Area of Tianjin as example and carries on the comparative study on the spatial interpolation of the buried depth and thickness of foundation soil. Such cross validation evaluates the interpolation accuracy and interpolation effect of ordinary Kriging, inverse distance weighted and thin-plate splines with tension. In addition, it focuses on the influence of spatial scale and the number of geotechnical investigation drillings on interpolation effect, and gives the optima spatial scale and drilling quantity. Under the 2000 m×2000 m and the original scale, we compared the statistics of the engineering geological zoning of foundation soils in different buried depth and thickness of each level distribution area. On this foundation, this paper analyses the change of the spatial interpolation, which is about of buried depth and thickness of standard foundation soil. The results show that with the method of ordinary Kriging interpolation and under the 2000 m×2000 m scale, the spatial interpolation of foundation soil in the Binhai New Area of Tianjin is the best. It can accurately explore the spatial distribution of foundation soil.