The invention relates to a corrosion clamp for a silicon cup, which comprises a mounting block of which a central area is provided with a corrosion hole, and one end of the mounting block is convexly provided with a positioning block which forms a step with the mounting block; the mounting block is provided with a pressure plate corresponding to an end part provided with the mounting block, the pressure plate is provided with a top plate which is provided with a pressure sheet, and the pressure sheet is in fastening connection with the fixing block; and the top plate and the pressure plate are in fastening connection. In the invention, through the corresponding match between the top plate, the pressure plate as well as the pressure sheet and the mounting block, a round sheet is placed between the mounting block and the pressure plate, and a sealing ring is arranged on the edge at the end part of the round sheet, therefore the edge of the round sheet can be effectively protected. A second connecting block is arranged on the pressure plate so as to reduce a contact area between the pressure plate and the round sheet to form soft contact and prevent the round sheet from being damaged. The invention has simple structure, low protection cost, good protection effect, safety and reliability.