Abstract: In order to study the generation mechanism and dynamic physical properties of the secondary arc, the combination of low-voltage simulation experiment and simulation modeling is used to analyze the movement characteristics of the secondary arc and the plasma state before the start of secondary arc. Based on high-speed camera shooting pictures in low-voltage simulation experiments, the arc movement characteristics were analyzed, and the effects of different secondary currents on the characteristics of the secondary arc are compared. The results show that the arc discharge channel is narrow and the motion is intense. At the same time, the discharge trajectory has obvious repeatability and is always in the short-circuit arc residual plasma. The greater the secondary current, the longer the duration of rekindling of the arc. Based on the combination of the general form of the coefficient partial differential equations and the classical drift diffusion model, the secondary arc theoretical model of the numerical simulation is obtained, and then the realization method based on the finite element software COMSOL is given. Transient analysis was used to simulate the discharge, diffusion and dissipation process of the arc in the short-circuit arc discharges. The distribution of electric fields and microscopic particles and the reaction process during the discharge are investigated. Simulation modeling results and low-voltage simulation experiment results have a high degree of coincidence in time and space. The simulation results show that short-circuit arc mainly includes two processes of corona discharge and arc discharge caused by short circuit, and the former has very short duration. In the process of discharge, the electron density of the lead arc discharge shows a trend of increasing first and then decreasing, and it has different characteristics from the general streamer discharge. The distribution curves of positive and negative ion concentration changes are consistent, but there are slight differences. When the ion response approaches the end of the simulation time, the ion concentration is higher than the initial level, which proves that the short-circuit discharge increases the spatial ion concentration, providing the necessary environmental conditions for the subsequent generation of the secondary arc.