Abstract: 11 NECP reanalyzed data,MM5 numerical modeling data,Doppler Radar data and lighting data have been used to analyze the dynamic characteristic,radar echo and CG lighting features of an extra territorial hail event on June 29th，2009 in Yunnan Province.Research results indicate that -meso scale convective storm and -meso scale squall line,which caused by the interaction of north-west cold advection and high-energy,high-humility air flow around tropical depression,initiated the hail event.Collision and convergence between invasive northeast wind and northwest wind promoted convective activity.The convective instable energy assembled before the hail,and reached peak value when the convective system developed to maturation period.The increasing of vertical wind shear speeded the energy exchanging on upper layer,then the instable energy was released,leading to the breaking out of severe convective weather.With the drawing near of the hail,height of the maximum value of vertical motion was lower than the height of 0℃ layer,and that phenomenon was beneficial to the formation of hail.There was cold advection transporting on the layer of 500hPa before the hail,causing the formation of cold core,and drawing near of the hail the height of cold core hoisted obviously.During the whole lifetime of storm,the frequency of CG lighting was very low.At the maturation stage of storm,there was a period in which positive CG lighting happened suddenly in an intensive way.Then the percentage of positive CG lighting increased obviously which was corresponding to the happening of severe weather.