Abstract: In order to avoid the hail disaster causing unnecessary loss to the society and achieve the purpose of disaster prevention and reduction and the hail weather forecast is done accurately, a causative analysis was performed of a typical severe hail event on June 2012 in Weifang City by using the routine observational data, radar and FY-2E TBB data, The result showed that: the severe hail event occurred on the circumfluence background of northeast cold vortex and forward trough. Violent updraft offered dynamic condition. The surface mesoscale and microscale convergence line triggered the weather. The severe vertical wind shear and an appropriate height about 0℃ layer and -20℃ layer would be advantageous to the hail augmentation. In addition, the weather occurred in the most vigorous period of convective cloud cluster, the location was from the motion direction front of cold cloud top of exceeding 232 K to the bigness of isotherm gradient, this had a good indicative effect for the forecast of severe hail event region.