Interferometric synthetic aperture radar (InSAR) has come to provide an important type of technology for monitoring wide-area and long-term ground movement. It has been widely applied to survey areas with landslides. Achache et al.¹ demonstrated the ability of InSAR to monitor small displacements at the scale required for large landslide monitoring and acquired the same trend as that of ground-based measurements. Soon after, Fruneau et al.,² Vietmeier et al.,³ Rizzo and Tesauro,⁴ and Squarzoni et al.⁵ began to apply InSAR technology in landslide monitoring and compared the trends and results with ground-based measurements. Then, international experts and scholars carried out more in-depth studies of the application of the InSAR technique to landslide monitoring, and the emphasis of research changed from validation of monitoring results to quantitative analysis of monitoring accuracy.^{6 – 12} Next, high-accuracy monitoring methods, including persistent scatterer InSAR,¹³ small baseline subset InSAR (SBAS-InSAR),¹⁴ coherent point target,¹⁵ stable point network,¹⁶ StaMPS,¹⁷ and SqueeSAR,¹⁸ were proposed and applied.^{19 – 35} To further improve region investigation and monitoring accuracy of landslides, InSAR has been combined with optical remote sensing, Global Navigation Satellite System, corner reflectors, and ground-based radar.^{36 – 45} However, due to the influence of complex regional topography and land use, improving the locating and monitoring accuracy of time series (TS)-InSAR in detecting the development of regional landslides remains a problem that urgently needs to be solved. Plank et al.⁴⁶ presented a geographical information system procedure to predict the areas of layover and shadowing due to the geometric distortion of radar image caused by rugged terrain. Notti et al.⁴⁷ used various persistent scatterer interferometry techniques to map and monitor landslides in various mountainous environments to improve the extraction density of permanent scatterer. Wang et al.⁴⁸ and Xie et al.⁴⁹ also carried out studies on the location and monitoring of landslides in alpine canyon areas by applying InSAR technology.

Landslide disaster has happened frequently in our country. Monitoring and early warning are the main means to effectively reduce the harm of landslide disaster. Different from the traditional method of monitoring, differential interferometry synthetic aperture radar (D-InSAR) measuring technique has the advantage of detecting and penetrating earth surface in all weather conditions and in all time, obtaining continuous and large-area deformation information. Taking the Jinpingzi Landslide of Jinshajiang valley as the research object. The monitoring technique of three orbits difference, the basic method of D-InSAR, is used to obtain surface deformation value. Research results show that the deformation value of Landslide boundaries is larger than the surrounding area, and the D-InSAR technology is a feasible approach for monitoring landslide.