Restoration of the original topography is the basis for the study of ancient seismic landslides in loess areas. The No.1 landslide in the Pangou Group, Sanhe Village, Pingfeng Township (Xiji County, Ningxia Hui Autonomous Region) was taken as an example in this paper. Satellite remote sensing interpretation and field survey were adopted to collect the current topographic data of the landslide. Based on the principle of equal volumes of landslide bodies before and after sliding, MATLAB was used to restore the original topography of the No. 1 landslide using 3D surface interpolation technology. The surface shape of the restored landslide's original topography is generally convex, with a slope distribution range of 12°—15°. Finally, the rationality and feasibility of the restoration results were demonstrated by the slope distribution range of the loess geomorphic units and the landslide stability calculation. Results provide a novel approach for the restoration of the original topography of ancient seismic loess landslides that lacks the topography data before sliding, thus providing important theoretical significance and engineering application value for related studies.