Abstract: In this paper, relationships between seismic intensity and peak ground shaking are studied under no specific condition, or considering the number of storeys of the building and site category separately or in combination, based on the data of mean peak values of horizontal ground motion recorded during strong earthquakes. Then, according to statistical results, the variation of mean peak value with intensity rating is discussed, and schemes of peak ground velocity, peak gound acceleration or response spectrum of design earthquake converted from intensity rating are recommended. Finally, a methodology converting response spectrum of design earthquake to seismic intensity is also discussed; and a conversion scheme is recommended.