Abstract: In recent years, synthetic aperture radar interferometry has been rapidly developed as a new type of space geodetic technology, which has the advantages of all-weather, all-day wide range monitoring with high precision, which can provide technical support for deformation monitoring of foundation stability in linear engineering. Focusing on collapsible loess geological area in Huixian section of the South-to-North Water Transfer Project, we collected 90 scenes of Sentinel-1 A in the study area from April 2015 to March 2019. We used the time series InSAR technology to extract time series of deformation and derive the annual average deformation rate. Based on the data, we studied the correlation of subsidence with soil moisture and the rainfall amount. As a result, the spatial-temporal evolution characteristics of subsidence in the region are obtained. The study can provide scientific basis for the foundation instability harnessing of the main channel of the South-to-North Water Transfer Project.