<p>This study innovatively investigates the seismic performance of wavy steel plates (WSSPs), integrating a novel seismic damper (WSSPD) to improve energy dissipation capacity. The multi-layer wave-shaped plate method is employed to achieve more plastic zones under cyclic loading, aiming to support energy dissipation within structures. Two experimental tests were conducted to evaluate the seismic behavior of the WSSPs and a newly proposed wave-shaped steel plate damper (WSSPD). In the first experiment, twelve specimens with varying geometries were subjected to a parametric study to evaluate the energy dissipation capabilities of WSSPs under cyclic loading. In the second experiment, based on the insights gained from the first test, WSSPD was proposed to enhance seismic performance by dissipating energy through the yielding of wavy steel. Geometrical parameters of WSSPs, such as thickness, radius, and wave number, directly affect their energy dissipation capacity. As the radius decreases, especially to less than 60&#xa0;mm, and with increasing thickness and wave number, the energy dissipation capacity increases. Test results show that the WSSPD exhibited stable hysteresis behavior and excellent energy dissipation capacity. During the entire test process, the damper dissipated energy effectively and demonstrated high strength and resilience. The WSSPs retained significant energy absorption even after rupture occurred during late loading. Based on the experimental analysis of damper energy dissipation, a theoretical approach was applied to investigate the elastic and plastic behavior of WSSP dampers, enabling the calculation of key parameters such as elastic stiffness, yield displacement and yield force of the wavy steel dampers. The derived equations provide accurate predictions and can be used for future design improvements.</p>