In this paper,the boring data and 1 321 small-moderate recordings in the western United States in recent years were collected,the magnitudes range M3. 5 ~ 6. 5,and the small-moderate recordings with boring data were classified by the criterion in the Code for Seismic Design of Building( GB 50011—2010) in China,the attenuation relations of peak ground acceleration in sites category Ⅰ,Ⅱ and Ⅲ were obtained and their characters were also analyzed. Which were compared with others' attenuation relation of the ro...