A sealing disc for vacuum closure suitable for using in reciprocating movement to an open position or a closed position to open or seal a metallic valve port of a vacuum valve, the sealing disc at least comprising: a base, the base having a first surface and a second surface opposite to the first surface; and a sealing plate, the sealing plate connecting around the base, wherein the sealing disc is adapted to simultaneously bear a closing force applied from an inside of the vacuum valve and an atmospheric pressure applied from an outside of the vacuum valve in the closed position, so that a first sealing surface of the sealing plate is capable of rotatably abutting against a second sealing surface in the valve port of the vacuum valve with the closing force and the atmospheric pressure to maintain vacuum closure of the valve port, wherein the sealing plate is consisting of: a first wing plate, the first wing plate is connected around the base at a first ring joint and extends outwardly in a direction away from the first ring joint at a first included angle relative to a ring surface of the first ring joint on the second surface of the base; and a second wing plate, the second wing plate is connected around the first wing plate at a second ring joint and extends outwardly in a direction away from the first surface of the base at a second included angle relative to the first wing plate, so that a third included angle is formed between the second wing plate and the ring surface of the first ring joint on the second surface of the base, wherein the first sealing surface, which is an arc surface, is located on an end edge of the second wing plate characterised in that, an angle value of the first included angle is 15 degrees, an angle value of the third included angle is 15 degrees, and a sum of the angle value of the first included angle, an angle value of the second included angle, and the angle value of the third included angle is 180 degrees, and in that the projection length of the first wing plate is approximately 0.8 to 1.5 times the projection length of the second wing plate and the projection length of the base is approximately 2 to 5 times the projection length of the first wing plate. a base, the base having a first surface and a second surface opposite to the first surface; and a sealing plate, the sealing plate connecting around the base, wherein the sealing disc is adapted to simultaneously bear a closing force applied from an inside of the vacuum valve and an atmospheric pressure applied from an outside of the vacuum valve in the closed position, so that a first sealing surface of the sealing plate is capable of rotatably abutting against a second sealing surface in the valve port of the vacuum valve with the closing force and the atmospheric pressure to maintain vacuum closure of the valve port, wherein the sealing plate is consisting of: a first wing plate, the first wing plate is connected around the base at a first ring joint and extends outwardly in a direction away from the first ring joint at a first included angle relative to a ring surface of the first ring joint on the second surface of the base; and a second wing plate, the second wing plate is connected around the first wing plate at a second ring joint and extends outwardly in a direction away from the first surface of the base at a second included angle relative to the first wing plate, so that a third included angle is formed between the second wing plate and the ring surface of the first ring joint on the second surface of the base, wherein the first sealing surface, which is an arc surface, is located on an end edge of the second wing plate characterised in that, an angle value of the first included angle is 15 degrees, an angle value of the third included angle is 15 degrees, and a sum of the angle value of the first included angle, an angle value of the second included angle, and the angle value of the third included angle is 180 degrees, and in that the projection length of the first wing plate is approximately 0.8 to 1.5 times the projection length of the second wing plate and the projection length of the base is approximately 2 to 5 times the projection length of the first wing plate.