The effect of explosive charge structure and prefabricated fragment size on fragment velocity of axial pre-fragmentation warhead was studied by numerical simulation. The results show that hemispherical charge structure can improve the fragments' velocity significantly, and the ratio 1.0 for curvature radius of hemispherical liner to charge diameter results in maximum fragments velocity. Tungsten column can attain a greater velocity than the tungsten balls with same mass for the both. On this basis, the effect of axial symmetry and uniformity dislocation arrangements on velocity of tungsten column was studied, and the conclusion obtained is that uniform dislocation arrangement can increase muzzle velocity significantly. These conclusions maybe guide of studies on prefabricated fragmentation warhead design.