The invention provides a prestress damping spring, and relates to the technical field of damping springs. The prestress damping spring comprises a sleeve and two damping spring assemblies arranged inthe sleeve, wherein the two damping spring assemblies are symmetrically arranged relatively to surfaces contacted with each other. Each damping spring assembly comprises an oil cylinder, a pull rod, aguiding cover, a liquid spring, an end cap, a piston rod, a piston head and a damping medium, wherein one end of the pull rod is stretched into the oil cylinder, and connected with one side of the guiding cover, the guiding cover is arranged in the oil cylinder in sliding mode, the other side of the guiding cover is connected with one end of the piston rod, the other end of the piston rod is connected with the piston head, the piston head is arranged in the oil cylinder in sliding mode, the piston head is provided with a flow guiding hole which communicates with two sides of the piston head,a space between the two sides of the piston head is filled with the damping medium, the end cap is arranged between the guiding cover and the piston head, and sleeves the piston rod, the end cap is fixedly arranged in the oil cylinder, and a space between the guiding cover and the end cap is filled with the liquid spring. The prestress damping spring is long in use life, and good in energy dissipation and shock absorption effect.