In current simulation studies on the impact of wildfires on the electric field of transmission line gaps, the relationship between burning particles and conductor spacing, as well as the electric field distortion effect, remains unclear. Additionally, the influence of meteorological factors and vegetation characteristics on the spatial distribution of burning particles has not been considered. To address this, a highly coupled multi-physics optimization simulation model integrating thermal, flow field, electric, and particle motion is developed based on simulated experiments and real-scenario parameters. This model combines micro- and macro-scale perspectives to analyze the intrinsic mechanisms of electric field distortion in transmission lines caused by wildfires. After verifying the model's accuracy, the proposed model can simulate flame combustion at different stages of wildfires and particle motion in transmission line gaps at a microscopic level, while also providing theoretical support for macro-scale analysis of the influence of vegetation characteristics and meteorological factors on gap insulation performance. The results show that the electric field on the conductor surface during a wildfire is approximately 7.14 times that under normal conditions. The spacing between burning particles and transmission conductors affects the electric field distortion effect, with the maximum distortion ratio and range beginning to rise significantly and gradually stabilizing when the spacing is between 0.2 and 0.15 meters. Vegetation characteristics and meteorological factors influence the insulation performance of the gap by altering the spatial distribution of burning particles in wildfire gaps. The research findings contribute to evaluating the safety of transmission lines during wildfire disasters and provide a theoretical basis for emergency response strategies.