Abstract: Open-pit mining of mineral resources often leads to slope instability and triggers hazards such as landslides, posing significant constraints on the sustainable development of both the mining environment and local socio-economy. This study focuses on the Manjiazhai open-pit mine and employs ascending and descending Sentinel-1A data (January 2020 to June 2021) to monitor slope deformation using the Small Baseline Subset Interferometric Synthetic Aperture Radar(SBAS-InSAR) method. The one-dimensional line-of-sight(LOS) deformation from multiple tracks was decomposed into two-dimensional displacement fields, yielding deformation velocities and time-series results in the east-west and vertical directions. The slope generally exhibited gradual deformation, with certain localized areas showing accelerated movement. The east-west deformation rate ranged from-545 to +423 mm/a, while the vertical deformation rate varied between-279 and +110 mm/a. By combining geological data and rainfall statistics from the monitoring period, internal and external contributing factors to slope instability were analyzed. Furthermore, the accuracy of InSAR-derived results was validated using total station monitoring data from 19 control points, showing an average error of ±11 mm and a root mean square error of ±14 mm.