Based on NCEP/NCAR reanalysis data, aerial exploration data, and Doppler radar data of Zhaotong, the hail disaster in Yiliang on August 20,2018 was analysed. The results indicate that: ①This hail weather was a local server convection weather caused by multi-cell storm. ②The sounding map revealed features such as inversion layer, horn shape and vertical wind shear. ③Radar echo characteristics show features such as false apex echo and weak echo region. ④ Vertically integrated liquid water content(VIL) before and after hail has jumped and steeped. ⑤Hail suppression has a weakening effect on the development of convective storm. However, grasping reasonable working time is the key to the success of hail prevention.