Abstract: The soil water characteristic curve(SWCC) of an unsaturated soil defines the relationship between the matrix suction and the water content. It is closely related to the permeability and shear strength of unsaturated soils. In this paper, based on statistical analyses of the soil water characteristic curves(SWCCs) and particle size distributions(PSDs) of 100 sand samples, a probabilistic method is suggested to predict the SWCC based on PSD through the commonly used VG model. The validity of the developed model is then assessed through 30 sets of independent data. Results from this study show that SWCC cannot be uniquely determined based on PSD. Compared with the existing methods, the proposed method can not only predict the most probable SWCC, but also the variability of the SWCC such that the error associated with the prediction model can be explicitly considered.