The numerical simulation of lethality enhancement device of explosively drive reactive rods was carried out to investigate the effect caused by the arrangement mode, arrangement radius and buffer materials. Results show that the collision between reactive rods can be effectively avoided and the stability significantly enhanced when the angle between the radial arrangement of two layers is 11.25° and the radiuses of outer and inner layers are < 85 mm and >37 mm, respectively. The pressure that inner layer rods bear decreases with the increase of arrangement radius. All of the polystyrene, polyethylene and polyurethane can be used as buffer material in the lethality enhancement device, but the scope of velocity of these rods is smaller, the convergence is faster and the spatial distribution is better when polyurethane is used.