Abstract: 175 horizontal accelerograms had been obtained during the Heicheng and the Tang-shan earthquakes. The effects of local soil conditions, seismic magnitudes and epicentral distances on the normalized response spectra were studied by means of the statistical analysis and their relations were examined by "the moving average method". The probabilistic distribution of β in the different periods is in good agreement with Jog-normal distribution. The results show that there are significant effects of the soil condition and the earthquake magnitude on the response spectra. Finally, 138 earthquake records in the western region of the U.S. were taken to compare with those obtained in China. As a results, some suggestions for aseismic design ia China are presented.