Abstract: Based on three-frame synthetic aperture radar (SAR) data derived from ALOS satellite sensor PALSAR, a three-pass differential SAR interferometry (D-InSAR) technique was used to analyze landslide activities in the Wudongde Hydropower Reservoir area at lower Jinsha River, and high accuracy ground displacement values were acquired by this method. The classification of these ground displacement values by sliding velocity and displacement clearly illustrated the ground activity deformation states of various zones in the studied area were clearly obtained, determined some potential moving landslides and active landslides and identified the dangerous zones of landslides. For an active landslide numbered No.L1R-6, the deformation detected by D-InSAR analysis shows an accordance tendency with the one by global positioning system (GPS) monitoring. In the end, single-point errors which existed in the result of D-InSAR technique were analyzed and a grid function error interpolation method of D-InSAR and GPS was proposed to improve the monitoring accuracy of D-InSAR technique.