Abstract: The capillary water, which is driven to rise due to the pressure difference on both sides of the meniscus caused by surface tension, cause the phenomenon of mud boiling and mud seepage in the silt roadbed. The rising height of capillary water is the key to preventing and controlling mud boiling and mud seepage in the roadbed. A calculation method to calculate the rising height of capillary water based on particle distribution characteristics is proposed on the basis of overcoming the experimental defects in measuring the height of capillary water. Based on the grain size distribution analyzed by the sieving tests, a fractal model for the grain size distribution of silt is established to systematically analyze the effects of fractal dimension, porosity, air-entry value and saturated permeability coefficient on the rising height and velocity of capillary water. The calculation results show that the rising height of capillary water is positively correlated with the time as a power function, and the rising speed of capillary water is only related to the fractal dimension of particle distribution, but not related to the porosity, air-entry value and the saturated permeability coefficient; the rising speed of the capillary water increases as the increase in the fractal dimension of silt grain size distribution.