The invention discloses a capacitive sensor lead sealing plug suitable for a vacuum or high-voltage environment. The vacuum or high-voltage environment required by a capacitive sensor can be kept by the sealing plug for a long period of time, so that the capacitive sensor accurately obtains measurement information. The lead sealing plug comprises a sensor lead connector and a test instrument lead connector; the sensor lead connector comprises a pipe joint, a shield soldering lug, an insulating cone, a bonding wire cone, a spacing block and a bonding wire plate; the test instrument lead connector comprises an insulating seat, a cable transfer tube and a bonding wire head; a sensor lead passes through the pipe joint; a metal core wire of the lead sequentially passes through the shield soldering lug, the insulating cone and the bonding wire cone and is welded on the end surface of the bonding wire cone; and the metal spacing block is welded on the end surface of the bonding wire cone. A test instrument lead passes through the bonding wire head; the metal core wire of the test instrument lead sequentially passes through the cable transfer tube, the insulating seat and the bonding wire plate and is welded on the surface of the bonding wire plate; the bonding wire plate is in contact with the metal spacing block; and finally the sensor lead and the test instrument lead are connected through a sleeve nut, so that the sealing target is achieved.