Electrical tracking is one of the main reasons for the deterioration of insulation surface. According to the problem of the surface electrical tracking erosion of insulation used in the high-voltage mining cables, the Ethylene Propylene Rubber samples with different electrical tracking development stage were selected in the paper. The relationship between the surface electrical tracking erosion degree of Ethylene Propylene Rubber and return voltage were analyzed. Characteristic parameters, which including the maximum value of return voltage, the constant of dominant time constant and the initial slope of return voltage were calculated based on the return voltage curves. It has been found that the maximum value of return voltage, the constant of dominant time and the initial slope of return voltage are closely related to the electrical tracking development stage. The constant of dominant time is significantly reduced with the increasing of the surface electrical tracking erosion degree. Research results demonstrate that the severity degree of electrical tracking erosion can be discriminated with Return Voltage.