Abstract: One high loess landslide, which was located in Yili Region of Xinjiang, reactivated and caused long-distance road burying and river blocking on April 30, 2019. About 5.04×10⁵ m³ of loess body was cut out along the high sliding position, and impacted shovel scraping ditch and bank slopes on both sides. However, so far it is difficult to understand the mechanism of unscheduled landslide reactivation. Based on detailed field investigation, remote sensing image identification, meteorological data analysis and loess characteristic test, this paper attempts to determine the formation and evolution history, movement process and reactivation mechanism of loess landslide.The results indicated that in the past this landslide had experienced two large-scale sliding failures, and in the meantime showed different degrees of inherited cumulative deformation failure annually with the development of slope ground fissures and cracks. The rapid snow ablation and infiltration drived by the abnormal temperature rising in spring was the most important influencing factor on deformation evolution of the loess landslide, and the coupling of thawing water and rainstorm in spring was the fundamental reason controlling the occurrence of loess landslides.Based on the successful disaster emergency response process after the disaster occurrence, a multi-department linkage highway disaster emergency response model based on early warning is proposed. Accompanying with the increase of regional grazing activities and climate warming, this loess landslide will have a great potential risk of reactivation sliding in the future. The study can provide a new perspective for researching the formation,evolution and failure mechanism of landslides in frozen regions, and have great significance for serving the traffic construction of One Belt and One Road in Xinjiang.