The invention discloses a thyristor replacement tool for vertically adjusting opening and closing of a pair of calipers. The thyristor replacement tool comprises a rectangular housing, wherein a horizontal through hole, a vertical through hole and a gear groove are formed in the housing, a columnar rack rod, a spring and a connecting column are arranged in the horizontal through hole, a rack is arranged on the side of the columnar rack rod, one end of the columnar rack rod extends out of the housing, the other end of the columnar rack rod is connected with one end of the spring, the other end of the spring is connected with one end of the connecting column, one end of an outer partition plate is installed at the other end of the connecting column, and one end of an inner partition plate is arranged on the side close to the outer partition plate, of the housing. A gear rotation rod penetrates through the vertical through hole, limiting plates are arranged on the gear rotation rod and are located at the upper portion and the lower portion of the vertical through hole respectively, and a gear is arranged on the gear rotation rod, located in the gear groove and matched with the rack of the columnar rack rod. During operation, an outer supporting point is not needed, separated force is elastically controlled by the spring, too large force is avoided, and a thyristor is protected.