In this paper, amplification coefficient (ks) of peek ground motion with different exceedance probability in types Ⅱ and Ⅲ sites, Shandong Province was estimated by analyzing the data of seismic response of soil layer from 358 and 140 drills from types Ⅱ and Ⅲ sites separately. From the results, one can conclude that: 1) the scatter plot of ks data shows that it generally obeys normal distribution; 2) ks decreases with the increase of the strength of incident ground motion, a phenomenon more apparent in type Ⅲ sites than in type Ⅱ sites; 3) for type Ⅱ site, with the increase of depth of the top surface of bedrock where ground motion incident, ks would increase gradually to a stable value until it reaches a depth up to approximately 20 meters or larger, while type Ⅲ site ks is normally insensitive to the depth; and 4) the average of ks for type Ⅱ site is 1.47, slightly larger than that used in the Seismic Ground Motion Parameter Zonation Map of China (GB18306-2001).
