Abstract: This paper introduces the single-phase terminal structure and electric field of 35 kV three-core cable, analyzes the main causes of the voltage-induced thermal defects of the cable terminal and the positive correlation between the phase-to-phase temperature difference on the surface of the cable terminal and the severity of the defect, combining with the typical case of the voltage-induced thermal defects of the 35 kV cable terminal discovered by the infrared detection technology, and puts forward the maintenance and prevention suggestions of the voltage-thermal defects.It provides reference for preventing the hidden danger of the cable line in advance and reducing unplanned outage rate.