Earthquake-triggered slow-moving landslides are not well studied mainly due to lack of high-resolution in-situ geodetic observations both in time and space. Satellite-based interferometric synthetic aperture radar (InSAR) has shown potential in landslides applications, however, it is challenging to detect earthquake-triggered slow-moving landslides over large areas due to the effects of post-seismic tectonic deformations, atmospheric delays, and other spatially propagated errors (e.g., decorrelation noises caused unwrapped errors). Here, we present a novel InSAR phase-gradient-based time-series approach to detect slow-moving landslides that triggered by the 2016 Mw 7.8 Kaikōura earthquake. 21 earthquake-triggered large (> 0.1 km 2) slow-moving landslides are detected and studied. Our results reveal decaying characteristics of the temporal evolutions of these landslides, that averagely after 3.9 years since the earthquake, their postseismic velocity will decay 90% and close to pre-seismic level. Our study opens new perspectives for the research of the mass balance of earthquakes and helps reduce associated hazards.