The invention provides a single-cylinder vibration absorber. A main piston assembly adopts a gradient porous metal material with a three-dimensional mulithole as a damping element, the hydraulic oil in the compressing and recovering stroke enters the low-pressure side oil cavity from the high-pressure side oil cavity through the three-dimensional intercommunicating multihole of the gradient porousmetal material of the main piston assembly, the hydraulic oil is forcibly segmented and flowed by the metal wire when flowing in the micropores, the hydraulic oil and the multitudinous metal wires generate strong shearing and internal friction in the interface areas of the hydraulic oil and the metal wires to form a damping effect, wherein the gradient porous metal material comprises first-gradeporous multitudinous/a large-hole supporting flat plate, second-grade porous multitudinous/ a middle-hole supporting flat plate(P2), a central damping layer(P3), the gradient porous metal material adopts a symmetrical laminated structure and is tightly pressed by a mode of (P1)/(P2)/(P3)/(P2)/(P1). According to the device, the porous material supported by the gradient is designed, so that the premature fatigue fracture of the laminated metal braided mesh which serves as the main damping effect is guaranteed. The vibration absorber is excellent in performance and long in service life.