Abstract: The earthquake-induced slope displacement is an important index for assessing the seismic stability of slope systems. In existing studies, only the displacement caused by mainshocks is considered, with the displacement caused by strong aftershocks being ignored. To address this issue, totally 372 recorded mainshock-aftershock sequences are selected in this study, which are subsequently used as input motions for the Newmark sliding-block analysis. Based on the displacement data obtained, the optimal ground-motion intensity measure (IM) is identified, and an empirical displacement assessing model incorporating the aftershock effect on slope displacements is proposed. The results reveal that peak ground acceleration (PGA) is the optimal scalar of IM, and that PGA, PGV is the optimal vector of IM. The R² score of the empirical model developed is 0.927, indicating desirable predictive performance. For a given earthquake sequence, the aftershock effect is one of the most important factors affecting the predicted results among various empirical displacement models. It is necessary to account for the aftershock effect. The model proposed can be utilized in assessing the displacement hazard for slopes subjected to earthquake sequences.