Abstract: The existing lightning electromagnetic wave propagation research mainly obtains the qualitative influence law through theoretical analysis or hypothesis, and the research results have insufficient support for the application of lightning monitoring. To address the issues above, this paper constructs a lightning electromagnetic wave propagation model considering the real complex terrain and soil conductivity distribution, and takes the Xizang power grid wide-area lightning monitoring system as the research object; moreover, a quantitative calculation of the propagation delay and amplitude changes of lightning electromagnetic waves is carried out specifically for lightning detection stations, and based on this, a lightning positioning optimization method suitable for engineering applications is proposed. The research results show that: (1) The receiving time of lightning electromagnetic wave is mainly affected by the terrain. Within the 300 km range of 63 detection stations in Xizang, the complex terrain can lead to a maximum delay of 6 μs; the amplitude of lightning electromagnetic waves is jointly affected by terrain and soil conductivity. Terrain mainly increases the amplitude through the refraction and reflection of the waveform, while limited soil conductivity causes attenuation of the waveform amplitude. In relatively flat terrain areas, the distribution of conductivity has a significant impact on the amplitude, and conductivity can cause a 1/3 attenuation of the amplitude; in areas with complex terrain, the influence of terrain dominates and can enhance the waveform amplitude by more than one time. (2) Considering the terrain and soil conductivity, the lightning location error that needs to be corrected by the lightning monitoring system of Xizang Power Grid is mainly distributed within 400 m, and the area with location error between 0~200 m and 200~400 m accounts for about 70%; the area with positioning errors of 400~600 m and 600~800 m accounts for about 15%. After lightning peak current correction, it decreases in most areas, and the area where lightning peak current decreases accounts for about 90%.