Disclosed is a fixture including: a base including a bearing surface for bearing a T-CON board, and a limit mechanism for limiting displacement of the T-CON board in a direction parallel to the bearing surface; and a probe assembly for jointing with an upgrading lead port of the T-CON board, wherein the probe assembly is installed on the base and has an adjustable relative position with the bearing surface in a direction perpendicular to the bearing surface. When in upgrading, the T-CON board is arranged on the bearing surface of the base firstly, the position of the T-CON board is fixed by the limit mechanism, and the probe assembly is aligned with the upgrading lead port of the T-CON board, and is adjusted and moved in the direction perpendicular to the bearing surface so as to joint with the upgraded lead port of the T-CON board.