The utility model discloses a lifting device of spring board used for connecting the river bank boat and the river bank of a floating bridge, which comprises a bridge board and a spring board, wherein the rear end of the spring board is hinge combined with the upper edge of one end of the bridge board and the lower edge is provided therein with a lifting device which comprises two supporting boards. The upper ends of the two supporting boards are respectively fixed on two web boards which are arranged on the contiguous end of the bridge board and the lower ends of the two supporting boards are extended outside the lower surface of the bridge board. The lower surface of the spring board contiguous end is correspondingly fixed with supporting seats on two sides. A set of expansion rods consisting of a hollow screw rod and a pair of screw rods is respectively arranged between the corresponding supporting seats and the corresponding supporting boards, wherein one end of each pair of screw rods is respectively rotatably inserted into two ends of one hollow screw rod. The outer ends of the screw rod, the lower ends of the supporting boards and the supporting seats are all provided with pin holes. The outer ends of each pair of screw rods are respectively hinge combined on the corresponding supporting board lower ends and the supporting seats through plug pins. The lifting device of the spring board achieves low manufacturing cost and high working efficiency.