Abstract: The helium-hydrogen separation bed, as a critical component of tritium extraction system in fusion reactors, serves as the collection site for hydrogen isotope gases. Its adsorption separation efficiency and reliability can directly determine the extraction efficiency and reliability of tritium within the system. In order to further study the influence of the structure parameters on flow field distribution and resistance to guide the structure design. In this paper, a two-dimensional numerical model of the radial flow adsorption bed filter and the powder layer was established by coupling with COMSOL, and the influence of the bed filling characteristics, structural parameters and gas flow mode were simulated. The results show that when the particle radius is greater than 40 μm, the bed layer flow resistance increases small with the decrease of the particle radius. When the particle radius is less than 40 μm, the bed layer resistance increases sharply. With the decrease of porosity, the flow resistance increases gradually, and the increase range becomes larger. Considering the pressure resistance effect of the bed and the challenges in powder packing, the recommended packing porosity(ε) should be maintained within the range of 0.52-0.60. Through analyses of the bed height-diameter ratio, the cross-sectional area ratio, and the fluid flow mode on the fluid distribution, it is found that the bed height-diameter ratio of 7-12, the internal and external cross-sectional area ratio of 0.38-1.00 have more suitable flow resistance. It is verified that the CF-Π type radial bed flow mode is recommended. When the cross-sectional area ratio(S) ranges from 0.38 to 1.00, the pressure difference across the powder layer shows no significant variation with changes in S, and this range is recommended for implementation. Regarding fluid flow patterns, comparative analysis reveals that centrifugal structures exhibit superior pressure resistance uniformity over centripetal configurations, with the CF-Π configuration demonstrating optimal homogeneity. Therefore, the CF-Π configuration is recommended for radial flow adsorption beds.