Abstract: The insulation filling materials of high-voltage cable outdoor terminal were analyzed, and the experimental verification on the low-temperature performance of typical materials were carried out, thermal field and electric field simulation calculation on the insulation filling liquid-precast insulation component interface was conducted, interface defects and explaining potential discharge risks were simulated. It was proposed that the minimum temperature of the insulation filling liquid in the operating terminal is approximately equal to the ambient temperature. This conclusion can guide material selection and give suggestions for standardization, and selection verification of insulation filling liquid.