Abstract: With the increasing size of China’s power grid, the number of switchgear is growing, but the switchgear has a large number of internal devices, complex mechanical structure, closed environment, poor heat dissipation conditions, the temperature rise problem is becoming more and more serious, which increases the difficulty of the security guarantee. For the overcurrent temperature rise problem of switchgear cabinet, the overall modeling of switchgear cabinet is completed in SolidWorks, and the electric-thermal coupling simulation study is carried out by COMSOL software. The correctness of the simulation is verified by installing a thermal camera on the inner wall of the door side of the switchgear to monitor the temperature of the switchgear moving contacts and current transformer joints. Based on the theory of electric field and temperature field, the electrical and thermal characteristics of switchgear cabinet under overcurrent fault are introduced, and the change of temperature rise of switchgear cabinet under different overcurrent conditions is investigated. The experimental results show that under overcurrent fault, the temperature of the switchgear contacts is significantly higher than that under normal operation, which easily triggers the temperature change of the contacts, and with the increase of overcurrent, the temperature of the contacts increases linearly and nonlinearly.