Sectional material connecting piece

The utility model belongs to the technical field of plate connection, and particularly provides a sectional material connecting piece which comprises a flexible part and two rigid parts, and the flexible part can deform; the two rigid parts are connected to the two ends of the flexible part correspondingly, and the ends, away from the flexible part, of the rigid parts are provided with connecting structures used for being connected with the side edges of a wallboard. Two limiting mechanisms are installed between the two rigid parts, each limiting mechanism comprises two arc-shaped plates, the circle centers of the arc-shaped plates face the flexible part, the circle centers corresponding to the two arc-shaped plates coincide, the radiuses of the circles where the two arc-shaped plates are located are the same, the two arc-shaped plates are partially overlapped, and a locking piece is arranged between the two arc-shaped plates. The locking device is used for locking and unlocking the two arc-shaped plates; the