Abstract: Based on 3830/CC Doppler weather radar data in Puer,a city in Yunnan,and lightning detection system data and Micaps objective analysis data,severe convective storm systems in South Yunnan have been analyzed on 6th and on 7th in April 2007.The results show that cooperation of trough and shear line from the upper to the low layer,coupling action of partial west jet current,and vertical structure of dry and cold atmosphere on the middle-upper layer and warm and wet atmosphere on the low layer supply vapor,thermal,convectively unstable and dynamical conditions for severe convective storm systems.Vertical wind shear and MARC on the middle and low layer are favorable to declining ingoing updraft enhancement and supercell development,whose reflectivity is ≥60dBz,Echo Top-ET is ≥12km,and height of strong reflectivity (≥50dBz) is ≥7.5km.The Supercell presents many features of rear-notch echo,front-flank notch,WER(BWER),gust echo,hook echo,maxmesocyclone,MARC,echo wall,spire echo and overhang echo,which results in disaster weather of gale and hail and positive cloud-ground flashes(+CG).The Squall line has features of mesoscale convergence and radial gale,but convective echoes develop differently in its various position,where convective clouds with declining structure develop intensively to form Supercell,bring about disaster weather of gale and hail,and lead to positive charge field exposure on the upper layer and positive cloud-ground flashes(+CG) appearance,and where convective clouds with vertical structure develop correspondingly infirmly,produce short-time severe precipitation,and lead to that positive charge field on the upper layer is blocked by major negative charge field bellow and negative cloud-ground flashes(-CG) happen.