Abstract: Due to the limited borehole data obtained during constructions, it is inevitable to interpret the underground stratigraphic boundary with uncertainty, which affects the design reliability of pile foundation and other engineering projects.In this paper, a method was proposed to quantify the uncertainty of stratigraphic boundary with limited borehole data, and the influence on the characteristic value of the vertical bearing capacity of a single pile was discussed.Firstly, based on the borehole data from a power plant, the stratigraphic boundary was reconstructed and a large number of random field data was generated to quantify the statistical uncertainty of the stratigraphic boundary by Bayesian compressive sampling-KL expansion(BCS-KL) method; then, according to the stratigraphic boundary data, the uncertainty analysis on the characteristic value of vertical bearing capacity of a single pile was carried out.The results showed that a large amount of random field data generated by the BCS-KL method can well characterize the uncertainty of the stratigraphic boundary; when the borehole spacing was sparse, the characteristic value of vertical bearing capacity of single pile has difference of4 660.88kN in the95% confidence interval, showing great difference.It is of great significance to evaluate the influence of stratigraphic boundary uncertainty on the characteristic value of the vertical bearing capacity of a single pile for engineering design by BSC-KL method.