Limited by the receiving equipment and the number of records,little is known about the rocking component of ground motion which cannot be ignored in structural seismic response analysis. In order to reveal the engineering characteristics of the rocking component and facilitate the reasonable selection of ground motion parameters in structural seismic analysis,based on the “5·12” Wenchuan earthquake records,the spatial distribution characteristics of rocking component's amplitude,spectrum and duration and the attenuation law with the fault distance are discussed. The statistical characteristics of rocking component and translational component parameters are compared. The results show that:compared with the translational component,the peak value of the rocking component is much smaller,the energy duration is slightly smaller,and the characteristic period is larger. For the spatial distribution characteristics of rocking component parameters,the peak value has a directional effect along the direction of fault rupture propagation,while the directional effect of peak value ratio,characteristic period and energy duration is not obvious;Except for the characteristic period,the peak value,peak value ratio and energy duration all have hanging-wall effects. With the change of fault distance,the variation law of rocking component parameters are consistent with those of translational component parameters,which shows that the peak value decreases with the increase of fault distance,and the peak ratio,characteristic period and energy duration.