The utility model discloses a lateral shock absorbing device applicable to a long-span bridge. The lateral shock absorbing device applicable to the long-span bridge comprises a top plate, a bottom plate, an upper connecting plate, a U-shaped steel plate, cushion blocks, anchoring bolts, high-strength bolts, bolt holes and a slot hole. The top plate and the bottom plate are provided with the bolt holes and firmly connected to a bridge girder and a bridge tower respectively through the anchoring bolts; the U-shaped steel plate is a power consuming element and is arranged between the top plate and the bottom plate; the bolt holes are preformed in the upper connecting plate, and the upper connecting plate is fixed under the top plate through the anchoring bolts; the upper straight section of the U-shaped steel plate is arranged between the top plate and the upper connecting plate and is in no contact with the top plate; the end portion of the upper straight section of the U-shaped steel plate is provided with a bolt hole, the upper connecting plate is provided with the slot hole, and the upper straight section of the U-shaped steel plate is connected with the upper connecting plate through the high-strength bolt capable of freely sliding inside the slot hole. The lateral shock absorbing device applicable to the long-span bridge is used for resisting momentary impact generated during transmission of a lateral structure system of the long-span bridge to improve the shock absorbing performance of the long-span bridge.