The peak electric field shifting far away from the pn^- junction and nn^- junction under static avalanche in high voltage diode was investigated by the device numerical simulation in this paper. An analysis of the electric field gradient analytical model was used to explain the reason of the peak electric field shifting. The results show that the peak electric field shifting is essentially induced by the avalanche generated carriers under static avalanche and occurs even at a low reverse current density level. In addition, from the borderline of peak electric field shifting, it is deduced that, with the increases of the doping concentration of p buffer layer and base doping concentration, the peak electric field shifting occurs at the higher current density.