In this study, the effect of optimization design for seismic brass damper using concept of Quality engineering and FEM analysis has been confirmed by experiment with small-scale specimen. This seismic damper consists of C2800 brass rod bent in U-shape and mounting piece with steel. The fact that the total energy absorption until fracture was significantly improved by increasing the elongation of the material and changing some specific geometry of the damper is consistent with the conclusion drawn by the optimal design, therefore the authors concluded that the proposed approach is effective for design of seismic damper.