The analysis of deformation and failure mechanisms of embankment slopes under seismic action is crucial for slope engineering design: this study uses FLAC3D to construct a slope model, simulating failure forms under Wolong (WL), Lushan (LS), and Luding (LD) seismic waves and innovatively examining dynamic response distributions of acceleration, displacement, and stress at different slope positions and effects of distinct seismic sequences. Results show that (1) under WL waves, the slope remains undamaged with more sensitive slope midpoint acceleration responses, where WL/LS waves induce two low-amplitude fluctuations while LD waves trigger a single concentrated fluctuation with abrupt changes; (2) the displacements at all points increase linearly with the load. Under the LD seismic waves, the slope displacement rises linearly after a brief fluctuation and reaches the largest peak; (3) stress decreases with elevation due to geometric dispersion but mid-slope stress is most sensitive, with LS waves inducing large-amplitude abrupt stress fluctuations and the highest peaks; (4) the slope midpoint shows the most pronounced responses in acceleration, displacement, and stress (followed by the base and crest), with LD waves posing the most significant threat to slope stability.