Abstract: This study investigate and analyze a lightning strike fatality occurred in a sunny day in Conghua of Guangzhou in 2017. The lightning first hit a big tree, and then hit the head of a nearby person and killed him immediately. According to the occurrence time and location of the incident described by witnesses, and using the location data of Low Frequency Electric Field Detection Array (LFEDA) and Guangdong Lightning Location System (GDLLS) location data as well as Radar data from Guangzhou CINRAD-SA radar, the incident is identified as one lightning strike fatality caused by a "bolt from the blue". The accident discharge is found to be the first Return-Stroke (RS) with the current peak of -30.9 kA, which belonged to a Cloud-Ground (CG) lightning flash with 7 RSs. The flash initiated at an elevation of about 13 km. After the cloud development process of about 600 ms, the lightning channel extended outward from the cloud. The horizontal distance from the edge of the cloud anvil (0 dBz) to the return point is about 0.3 km, and the horizontal distance from the edge of the precipitation area (18 dBz) to the return point is about 1.8 km. According to the equivalent circuit model of lightning strike, we calculated the air breakdown voltage of side flash and found that the "jump point" between 1/3 and 1/4 above the trunk could form conductive path to the head of the victim. This paper assumes that the "jump point" is at 1/4 above the 13 m height trunk. Based on the Circuit Shunt Principle, the process of the incident can be inferred to as:The flash hit the tree and the current flowed to the "jump point", then, the 13.2 kA lightning current blinked directly to the victim and the victim also experienced the injury of 78.3 kV, while the witness who was 10 m from the lightning strike point only experienced 1.3 kV step voltage.