We have investigated the domain wall dynamic around the Walker breakdown field in ferromagnetic nanowires by means of micromagnetic simulation. The simulation is driven by short magnetic pulse 1-ns length with a systematic variation of applied magnetic strength. Interestingly, it is found that the domain wall structure exhibits transverse domain wall structure before the Walker breakdown field while the vortex/antivortex domain wall structure after the Walker breakdown field. The domain wall velocity increases as the applied field strength increases before the Walker breakdown field and decreases after the Walker breakdown field. The Walker breakdown field decreases as the width and the thickness of nanowires increases. We also analyzed the energy magnetization density system around the Walker breakdown field. It is revealed that the magnetostatic energy dominates of the energy system and the exchange energy tendency increases as the vortex/antivortex structures is formed in ferromagnetic nanowires.