Abstract: Landslide is the main type of geological hazard in mountain areas, which is a great threat to the important infrastructure. The research and monitoring about its formation mechanism is of great significance to the recognition and prevention of landslide. On the basis of field investigation of Tianchigong landslide, the authors in this paper comprehensively analyzed the landform, geomorphology, strata, lithology, geological structure and basic features of the landslide, and investigated the process of deformation and failure and the development trend in the landslide area. The horizontal displacement and vertical displacement of landslide surface, horizontal displacement of deep drilling, and the drilling gradient were monitored and comprehensively analyzed, combined with the comprehensive monitoring methods such as the real-time rainfall monitoring, drilling deep displacement monitoring and GNSS monitoring . The effect of the emergency treatment after landslide was evaluated based on the monitoring results. The results show that the stability of landslide is obviously improved after the emergency treatment, and the deformation trend is convergent. This research could provide technical support for the landslide rescue and the in-time operation of natural gas pipeline, and remarkable comprehensive benefits were obtained. The research vesults could provide important references for the emergency management of similar engineering landslide and effect evaluation.