Abstract: Capillary suction is one of the vital physical parameters to porous media and has been widely concerned in engineering practice. This paper combines the Gardner soil-water characteristic curve model and the structure parameters obtained by Micro-CT tomography at first. The unsaturated capillary rise model and a specific quantification for capillary rise in the porous media are then developed using the fitting relationship between suction and saturation and the finite difference method. Furthermore, laboratory experiments are carried out to confirm the availability of the model, where the narrow sub-washed sand is chosen as object. Parameters of the capillary rise process and the stable distribution of moisture are measured actually. Results indicate that a good agreement is presented between test and theoretical values. The proposed theory is feasible to predict the capillary rise and the moisture distribution of sand.