Abstract: Under the backdrop of global warming, the permafrost on the Qinghai-Xizang Plateau is degrading at an accelerated pace, and thermokarst landslides occur frequently, posing a threat to railway infrastructure. At present, the identification of thermokarst slumps mainly relies on single optical images, and the recognition accuracy is limited in those complex environments. Moreover, existing studies are mostly concentrated in remote areas, while research along the Qinghai-Tibet Railway is relatively scarce. To address these limitations, 87 Sentinel-1A descending-track images acquired from 2019 to 2022 were processed using the SBAS-InSAR technique to obtain surface subsidence and its spatiotemporal evolution in the Fenghuoshan segment of the corridor was revealed. Google Earth imagery was then used for visual interpretation to delineate the spatial distribution of RTSs. Furthermore, six controlling factors—including elevation, land surface temperature, and lithology—were incorporated to analyze the mechanisms driving RTS occurrence. The results indicate that: surface degradation is mainly concentrated in the western and northern parts of the study area, with a maximum subsidence rate of –54.20 mm/yr; a total of 62 RTSs were identified, with an average area of 0.02 km²; and RTSs are mostly found in areas with medium to high altitudes, low slopes, and siliceous sedimentary rocks. These findings provide a scientific basis for the early detection of potential hazards along the Qinghai–Tibet engineering corridor and offer valuable support for the safe operation and sustainable development of the Qinghai–Tibet Railway.