Abstract:On April 20, 2013, and the M7 earthquake occurred in Lushan county, Sichuan Province. Based on the 2 106 sets of strong ground motion data, using the simplified attenuation relationship model based on NGA, the random effect method was used to obtain the PGA, PGV, and pseudo-acceleration response spectra (PSA) (damping ratio=5%) period from 0.01 s to 8 s. Through contrast with the attenuation relationship in other parts of Sichuan, this model can well predict the strong ground motion attenuation of Lushan aftershocks. The attenuation relationship on both the rock site and soft site is consistent in the short-term with the outcome of Lu Dawei's model. In the case of long periods, however, the outcome of this model in the soft site is larger than that of Lu Dawei's model and is lower at rock site than that of Yu Yanxiang's model. Therefore, when using the attenuation relationship derived from this paper, special attention should be paid to the influence of site and period.