Abstract: Using the lighting data,Dopplar radar data and FY-2E satellite infrared data,a Mesoscale Convective System process in south-west of Yunnan is analyzed,The results show that the advantageous conditions of warm atmosphere and wet atmosphere are supplied by tropical depression moving west and east jet on the low layer.The negative cloud-to-ground (-CG) lightning is predominant to positive cloud-to-ground (+CG) lightning during the whole lifetime of MCS and -CG flash rate increase slowly with the fluctuations at the first developing stage.-CG lighting occupies absolute predominance and flash rates is above 150 times every 10 minutes as the same time as the +CG lighting increasing slowly at the ripeness stage,-CG lighting declines obviously and the +CG lighting insreaes rapidly at dissipating stage; there are three peak stages of -CG flash rate corresponding to three squall lines nicely,-CG lighting mainly clusters in the region that cloud top temperature is under -60℃ and the fore cloud top temperature gradient is largest at the ripeness stage,but +CG lighting disperses in the rearward of dense -CG lighting and the cloud center during the process of MCS;The mesoscale zonal echo with asymmetric configuration figures formed by many different scales of convection cells on Doppler weather radar;-CG lighting mainly clusters in the left rear region echo with high reflectivity (40dBz) and high Echo Top (10km) because of the sideling feacture of updraft inside MCS,that is not coincided to the Strongest echo region,the reion of echo top is positive correlate to that of -CG lighting;The +CG lighting begins to grow after the peak stage of -CG lighting,The +CG flash rate increases and disperses in the rearward of intense echo region or on the weak convective echo or sheet echo at dissipating stage,CG lighting emerge less in the blustery region(＞12m/s);the character of echo intensity 48dBz at -10℃ altitude layer,echo top15km can be the index of -CG Frequently Occur.