The invention relates to an insulation structure of a friction disc and an equipment body in a current-carrying friction wear testing machine. The friction disc is fixedly assembled at the external end of a transmission shaft; the transmission shaft is rotatablely assembled on the equipment body; a disconnecting surface is arranged on the transmission shaft of the exposed section at the internal side of the fixed assembly position with the friction disc; the disconnecting surface divides the transmission shaft into a left transmission shaft body section, a right transmission shaft body section and an end section; the left transmission shaft section and the right transmission shaft section have the same axis line and are fixed into a whole; electric insulated coating is coated on the disconnecting surface of at least one side. The insulated coating generally has thin thickness, light weight, large hardness, good rigidity and is not easy to deform when bearing the pressure; as the insulation type between the testing part and the machine body of a current-carrying testing machine, the insulation structure of the invention meets the insulation performance requirement at the high speed, improves the rotation precision and ensures the dynamic balance during the high-speed rotation process simultaneously, avoids the infidelity of the test results and correctly reflects the performance of the test objects.