Abstract: There are few studies on insulation aging characteristics of ethylene propylene rubber cable under electro-thermal aging. According to the above problem, electro-thermal aging test of mine-used ethylene propylene rubber cable was carried out, polarization and depolarization current characteristics of ethylene propylene rubber cable insulation under different aging time were analyzed, and characteristic parameters which could reflect insulation aging degree including aging index and depolarization charge quantity were proposed. The results show that color of insulation surface of ethylene propylene rubber cable gradually changes from white to brown with increase of aging time. In the late aging stage, white powdered material is generated in outer insulation layer, and many holes are formed in the insulation. Polarization current and depolarization current of the insulation increase gradually with increase of aging time. Change of the depolarization current is obviously in the early aging stage and small in the late aging stage. Aging index calculated by the polarization current and depolarization charge quantity calculated by the depolarization current increase with increase of aging time, which can be used as characteristic parameters to evaluate insulation aging state of ethylene propylene rubber cable.