The geographical environment of the Three Gorges Reservoir area in China is characterized by complexity, a humid climate, abundant rainfall, and frequent human engineering activities, resulting in frequent geological disasters. Slope instability is identified as a potential threat to infrastructure and the safety of lives and property in the reservoir area, highlighting the importance of landslide monitoring and mechanism research. The Jinjiling landslide in the Three Gorges Reservoir area was selected as the research focus. Time-series interferometric synthetic aperture radar(InSAR) technology was employed to obtain deformation information of the landslide, and the effects of varying rainfall conditions on the landslide were analyzed using Geo-studio software. The numerical simulation results show that, for the same amount of rainfall, prolonged rainfall duration exerts a more sustained impact on the seepage field of the landslide and reduces the stability coefficient of the landslide at the end of the rainfall event. In the deformation analysis, maximum deformation is observed within 3 hours of the rainfall onset under the condition of 20 mm/d rainfall intensity. The comparison between numerical simulation results and time-series InSAR deformation monitoring indicate strong consistency between the simulated deformation field and the deformation location identified by time-series InSAR monitoring.