The decomposition characteristics of SF6 insulation gas in the overheat fault condition provide reference for the overheat fault diagnosis of SF6 electrical equipment. Based on normal operation of high-voltage equipment, it is necessary to establish an overheating fault simulation test platform to simulate the generation of local hot high temperature to decompose SF6. In this paper, aiming at the fault temperature of high-voltage equipment, the coupling electromagnetic-fluid-thermal fields verified by e xperiments is used to optimize the current and flow-through component structure to obtain the local hot high temperature meeting the requirements. The calculation results show that the optimized structure and current can provide the temperature required for SF6 equipment fault simulation.