320 strong motion records of four sites are appropriately selected. The elasto-plastic dynamic analysis program is used to research the effects of characteristics of earthquake motion on elasto-plastic acceleration spectra, elasto-plastic displacement spectra, residual displacement spectra and reduced strength spectra. The study results are obtained as follow: 1) The value of elasto-plastic acceleration spectra, elasto-plastic displacement spectra, residual displacement spectra are increased with the amplification of seismic magnitude. 2) When site soil softens, the elasto-plastic acceleration, displacement, residual displacement of the same period are amplified in site Ⅲ and Ⅳ. On the contrary, site conditions of site Ⅲ and Ⅳ have nothing to do with elasto-plastic response spectra. 3) When ductility is greater than two, reduced strength spectra can be affected by seismic magnitude and site conditions. 4) Elasto-plastic response spectra of other protected earthquake intensity can be obtained by adjusting elasto-plastic response spectra of the standard protected earthquake intensity according to the ratio of PGA (protected earthquake intensity) to PGA (standard protected earthquake). So, some meaningful references are provided for performance-based seismic design for bridge.