The large reservoirs in the southwestern Alpine Canyon region are characterized by long reservoir banks and complex geological structures. The problem of finding the deformation zone quickly and efficiently is urgent and needs to be resolved. In this study, taking the area 110 km upstream of the Baihetan dam site as the study area, the applicability of various interferometric synthetic aperture radar (InSAR) techniques was summarized, and the small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) method was used to carry out large-scale disaster risk screening using multi-source satellite SAR data. A total of 40 hidden danger points were identified, with 22 of them being newly discovered. The differences in the deformation results from the multi-source satellite SAR data were discussed. By analyzing ComparSAR-based deformation monitoring results of a large reservoir, a new risk screening method for slopes in alpine-canyon regions can be provided.