Abstract: Soil particle size distribution (PSD) has been widely used in the estimation of soil-water characteristic curve (SWCC), and soil pore size distribution (POSD) has an important effect on SWCC, and the relationship between PSD and POSD is of great significance for the study of SWCC. Through the analysis of a large amount of experimental data, it is shown that there is a linear “ladder” distribution law between particle size and pore size in double logarithmic coordinates, and the larger the particle size is, the more obvious the linear “ladder” is; the smaller the particle size is, the “ladder” disappears gradually and tends to the SWCC. The smaller the particle size, the “ladder” gradually disappears and tends to linear distribution. Based on this, firstly, the relationship between particle size and pore size was constructed according to the linear “step” distribution law; secondly, according to the Young-Laplace equation, the particle size distribution function and pore ratio were introduced to establish a SWCC model considering the particle size grading and deformation of the soil. Finally, the model is verified by several sets of experimental data, and the results show that all the models proposed in this paper can conform to the experimental observations better, which verifies the reliability of the model.