Abstract: Helium-hydrogen separation bed is an important part of tritium extraction system. In order to deeply study penetration performance of the radial flow bed and guide the structure design, the mathematical model of radial bed breakthrough capacity was established by coupling material hydrogen absorption kinetics equation, mass transfer equation and fluid flow momentum equation in COMSOL Multiphysics, which was used to carry out parametric scanning of the characteristic parameters, and the effect of the model on the breakthrough capacity was analyzed. The results show that the breakthrough experiment results are in good agreement with the simulated data, and the model is reliable. The effect of temperature, height-diameter ratio and porosity on the breakthrough capacity was analyzed. The adsorption temperature of the bed is from room temperature to 343 K. In this temperature range, increasing the temperature has less effect on the length of the mass transfer zone and the concentration-time curve at the outlet. With the increase of the height-diameter ratio, the efficiency of the bed decreases significantly, in which the high efficiency is maintained for a longer period of time when the hieght-diameter ratio is 2.00-8.33. With the increase of porosity, the adsorption efficiency of the bed decreases significantly. Considering the adsorption efficiency, the flow resistance and the difficulty of powder loading, the powder porosity is recommended from 0.56 to 0.64. Therefore, the model established in this study can better predict the adsorption performance, and can be used to optimize the structure design basis and process parameters.