The utility model discloses a disc clamp with a limit structure; the disc clamp comprises a rotary chuck used for placing the disc, a rotary shaft driving the rotary chuck to rotate, and a driving mechanism driving the rotary shaft to rotate; the rotary chuck comprises a base, a clamp element arranged around the base, an annular body and the limit structure; the clamp element comprises a body portion and a clamp portion, wherein the body portion can self-rotate, so the clamp portion can move between an opening position and a clamp position; the annular body and the body portion of the clamp element form an engaged surface; the engaged surface can enable the body portion to be engaged with the annular body for self-rotation when the base and the annular body relatively rotate; the limit structure comprises a first and a second limit pieces arranged on the base and the annular body; when the base relatively rotates in a first direction against the annular body, the clamp portion moves from the opening position to the clamp position, the first and second limit pieces can contact so as to restrict relative rotation in the first direction, thus adjusting a force, applied to a side of a silicon sheet, of the clamp portion.