The embodiment of the invention provides a prestressing force damping device, prestressing force damping equipment and a bridge, and relates to the field of bridges. The prestressing force damping device comprises a machine body, a damper and a hydraulic spring, the damper is connected to the machine body, one end of the hydraulic spring is connected with the machine body, the other end of the hydraulic spring is connected with or abuts against a piston rod of the damper, and the hydraulic spring is used for pre-tightening the piston rod in the moving direction of the piston rod; and the prestressing force damping device has a first state and a second state, in the first state, external force borne by the hydraulic spring in the moving direction of the piston rod is smaller than or equal to prestressing force between the hydraulic spring and the piston rod and the piston rod is static, at the second state, the external force borne by the hydraulic spring in the moving direction of thepiston rod is larger than the prestressing force between the hydraulic spring and the piston rod and the hydraulic spring compresses to drive the piston rod to move. When the prestressing force damping device plays a role in supporting when the borne external force is smaller than or equal to the prestressing force and plays a role in buffering when the borne external force is larger than the prestressing force.