<p>The giant Mogangling paleo-landslide, located in Luding County on the eastern margin of the Tibetan Plateau, was triggered by the M7.75 Moxi earthquake in 1786. Over hundreds of years of geomorphological evolution, and following several major seismic events—including the recent Ms6.8 Luding earthquake in 2022—the internal structure of the landslide has become highly complex, posing a significant risk to the local community. In this study, we employed four geophysical methods to investigate the internal structure of the landslide body: electrical resistivity tomography, passive surface wave, horizontal-to-vertical spectral ratio, and ground penetrating radar, along with the borehole information, digital elevation model, and soil mechanics. The results obtained from these methods, which exhibit significant heterogeneity, indicate substantial internal deformation. In addition to the original sliding surface within the weathered bedrock, a secondary sliding surface was identified inside the overall landslide deposit revealed by the boreholes. This finding suggests that the landslide has undergone at least two major sliding events. The secondary sliding surface is relatively flat at the front of the bench and close to the water level of the previously dammed lake, implying that the second landslide occurred atop the first. These findings underscore the value of utilizing multiple geophysical techniques to study complex subsurface structures and provide critical evidence for more accurate risk assessments of the Mogangling paleo-landslide, which is vital for future mitigation and prevention efforts in this seismically active region.</p>