Cable telescopic protection device and cable bridge

The invention relates to a cable telescopic protection device and a cable bridge. The cable telescopic protection device comprises a sliding rail mechanism which is used for being installed on a bridge frame and fixedly connected with a first straight section part of a cable; the damping mechanism is connected with the arc-shaped supporting plate, and the arc-shaped supporting plate is used for being fixedly connected with the bending section part of the cable; and the rotary fixing mechanism is used for being arranged on the bridge frame and fixedly connected with the second straight section part of the cable. When the load which is applied to the bridge body by strong wind, sea waves and passing vehicles and acts on telescopic deformation of the bridge body is too large, and the deformation of the arc-shaped supporting plate is not enough to bear the load, the damping mechanism generates damping force to offset part of the load which cannot be borne by the arc-shaped supporting plate, so that the part of th