The invention relates to a damping device for sewage treatment equipment, which comprises a cylinder barrel. A piston rod is arranged in the cylinder barrel; both ends of the piston rod are respectively sleeved with a first guide sleeve and a second guide sleeve; a right lifting lug connected with one end of the piston rod is also arranged outside the second guide sleeve; an end cover is also arranged at the end part of the cylinder barrel, which is positioned at one side of the first guide sleeve; the end cover is connected with a left lifting lug; oil is arranged in a cavity formed by the first guide sleeve, the second guide sleeve and the cylinder barrel; the piston rod is also connected with a piston between the first guide sleeve and the second guide sleeve; and the piston comprises afixed piston and a movable piston, wherein the fixed piston is fixedly mounted on the piston rod, the movable piston is mounted in a movable limiting mode on the piston rod, and a first spring is connected between the fixed piston and the movable piston. The device can carry out two-stage energy consumption.