Abstract: By using monitoring data of lightning detection system,atmosphere electric field apparatus and the Dopplar weather echo radar and MICAPS 1白1? object analysis field,the strong thunderstorm process over Lower Latitude Plateau(Yunnan Province)on July 17,2006 is analysed.The results show that the advantageous circulation background of convergence field on the middle and low layer and wind direction shear from the low layer to the upper layer is supplied for the strong thunderstorm weather process,and the advantageous ambient condition of high energy and high humidity,strong instability and ascending motion are also supplied.The lightning detection net monitored 33 125 lightning return strokes,high density was in mid-Yunnan,the most density was 594 at 0.1癊?0.1癗 for 24 h,and lightning fastigium was from 16:00 to 17:00.On Dopplar radar there were 3 mesoscale convective systems(MCS)affecting Yunnan,echo intensity was from 40 to 55 dBz,and the mesoscale feature of the wind convergence,areas of the contrary wind and the large radial velocity were advantaged to the development of convective echoes,arousing thunderstorm weather and thunder phenomenon.