To better understood the characteristics of precipitation and lightning activities during a thunderstorms in Sichuan, by using the statistical and contrast methods, the features of the lightning activity and precipitation structure during a thunderstorm occurred in the southeastern Sichuan are analyzed. The results show that the heavy rainfall occurred in the flow field with low level convergence and upper level divergence, and the height of the local maximum precipitation zone located between 2 km and 5 km. After one hour of precipitation, the frequency of lightning flashes began to achieve the maximum, and the ground flashes were mainly negative CG (cloud to ground) flashes, and there were few positive CG flashes. According to the relationship between lightning activity and brightness temperature distribution, it is known that lightning activity occurs mainly in precipitation clouds with temperature being less than 220 K, and the areas of lightning activity are in agreement with precipitation areas. From the distribution of the total flashes and CG flashes, it can be known that negative CG flashes are distributed outside of the total flash area, and IC (intracloud) and CG flashes together impacted on the occurrence of lightning activities in the cloud system.The findings are useful to thunderstorm forecasting.