Damping performance curve is used to adjust the seismic response of structures with damping ratio different from the natural damping ratio， which is of great significance to simplified design and analysis of the structures with energy dissipating devices. In this paper， two performance curve parameters， namely the displacement damping rate η_d and acceleration shock absorption rate η_a， of the SDOF system under harmonic excitation with different natural periods were calculated respectively. The results showed that the η_d decreases with the increase of damping ratio under any natural periods； η_a also decreases with the increase of damping ratio in a short natural period， but increases in a long natural period； Both coefficients reached the minimum value at the resonance point. Moreover， the damping ratio decreases as the natural period close to the resonance point. Based on the results of the analytical solution， comparison and analysis were conducted for several famous seismic waves and the corresponding shock absorption performance curve was obtained， which was verified with the results obtained from time history analysis. Since the frequency components of simple harmonic wave are manifold， η_a tended to increase with the decrease of the damping ratio， which can be used to explain the structural seismic response law and theoretical reasons of the high damping and long period. In the end， an example is presented to verify the feasibility of the performance curve in practical engineering.