Abstract: To gain further insight into the characteristics of lightning activity during the whole life of a tropical cyclone (TC), World Wide Lightning Location Network (WWLLN) data, TC best-track data from the National Meteorological Center of China Meteorological Administration, black body temperature data from the Fengyun-4A satellite, and ERA5 reanalysis data are used to explore typhoon Mangkhut, the strongest typhoon that landed in China in 2018. The temporal and spatial distributions of lightning activity and its variation with intensity during the whole life of typhoon Mangkhut are studied, as well as the relationship between lightning activity and wind circle radius and the underlying surface. Results show (1) the three-circle structure of the lightning activity in Mangkhut: the highest density of lightning in the inner core, almost no lightning in the inner rainbands, and the largest amount of lightning in the outer rainbands. The inner core lightning has a different main occurrence time from the outer rainband lightning, which can also produce a large amount of lightning in the open sea. (2) The azimuthal distribution of lightning activity is closely related to TC intensity, geographical location, and environment and is different in different periods. (3) There is no clear relationship between lightning activity and wind circle radius. The lightning activity mostly occurs in the southeast and southwest, where the wind circle has a smaller radius. (4) During and around TC rapid intensification, the inner core lightning activity has a certain indicator effect on TC intensity intensification. Moreover, there is a good correlation between lightning activity and convective intensity in the inner core. (5) The existence of islands and land plays an important role in severe convection development. When the stream hits a higher terrain, it is forced to lift, forming lightning. The southwest direction of the TC is about 300km away from the southeast side of the island, and sufficient water vapor, heat, and more anthropogenic aerosols are observed, which are conducive to updraft development, thus generating lightning. These insights contribute to the application of lightning data in monitoring and early warning of mesoscale and small-scale severe convections in TCs.