Abstract: According to intensity data from the 2008 Wenchuan M_S8.0 earthquake, the simplified Newmark method was used to calculate the landslide displacement corresponding to the combination of rock-soil strength parameters of different rock groups in the Qingchuan county, Sichuan Province. Taking the goodness-of-fit between the actual and the predicted landslide data as the evaluation criteria, we analyzed the rock-soil strength parameters in the studied region. The results showed that the reasonable value ranges of rock-soil strength parameters of rock groups in most of the studied region were basically consistent with the ranges of recommended parameters of Standard for Engineering Classification of Rock Masses GB 50218—94. Referring to the parameters ranges determined in this paper, the evaluation accuracy of the earthquake landslide susceptibility level can be improved to some extent.