Beam stability is a major concern for the operation of the Taiwan Photon Source. Oneof the many factors to instability of electron beam is mechanical vibration of theaccelerator components. The TPS uses steel girders to support the magnets and vacuumchambers in the storage ring. Three pedestal and six mover assemblies support the girders.Multi-stage adjustable shock absorbers are designed for passive vibration damping, andpresently installed between the girders and the pedestals. Through adjusting the amount ofhydraulic fluid which bypasses the damping passage between two hydraulic chambers, thedesired damping coefficient of the damping absorbers can be achieved. Experimental resultsof modal testing presented in this paper show that the multi-stage adjustable dampingabsorbers under the assembly of the girders reduced the level of girder vibration.