The invention discloses a conduction current-space charge combined measurement device, and the device comprises a grounding metal shielding cover, a grounding metal plate, a signal amplifier, and a single-pole double-throw switch. The interior of the grounding metal shielding cover is provided with a high-voltage metal electrode and is provided with insulating resin. The grounding metal shielding cover is provided with a high-voltage DC conducting rod and a high-voltage pulse conducting rod. The high-voltage DC conducting rod is connected with a high-voltage metal electrode, and a high-voltage capacity is connected between the high-voltage pulse conducting rod and the high-voltage metal electrode. The grounding metal plate is provided with a metal electrode, and a metal external electrode and a central metal electrode, which are insulated with each other, are disposed above the grounding metal plate. The signal amplifier is connected with a signal wiring port and the metal electrode. The single-pole double-throw switch is connected with the central metal electrode, so as to enable the central metal electrode to be connected with a conduction current signal wiring port or to be grounded. The device can achieve the combined region of the conduction current and space charge in the same region, is high in measurement precision, and is high in reliability of a measurement result.