Abstract: Rock collapse is one of the most common types of geological disasters in slope engineering. It is sudden and destructive, and poses great threats to the traffic road, construction personnel and machinery below. Real-time monitoring of dangerous slope can reveal its deformation response characteristics, which is of great significance for emergency warning and comprehensive prevention and control of slope. In this paper, the slope at the entrance of diversion tunnel of a hydropower station is taken as the research object and a monitoring technique combining GB-InSAR and terrestrial scanning laser was adopted. Through coordinate transformation, the corresponding relationship between the terrestrial scanning laser coordinate system and the GB-InSAR coordinate system is established, and the points in the 2 D radar image area are matched with the terrain points, so as to realize the real-time monitoring of three-dimensional integral deformation of the slope. Based on the monitoring results, the overall stability of the slope and the evolution law of local dangerous rock mass are deeply analyzed. The results show that the overall stability of the slope is good, but due to the fragmentation of rock mass and the development of joints and fissures, the regional stability of local dangerous rock is poor, and the deformation of some areas is significantly affected by rainfall and construction disturbance.