Abstract: To explore the monitoring sensitive parts of the rock tetrahedral wedge, we used our self-developed slope model test platform and carried out a physical simulation test of the tetrahedral wedge rock slope. We monitored the internal displacement and internal stress at the structural plane of the wedge in the whole process of sliding instability. The results show that with the increase of sliding displacement of the wedge, the difference of displacement change rate at each displacement monitoring point is smaller, and the overall sliding characteristics of wedge are more obvious. In the early stage of the wedge instability process, the sensitive parts of displacement monitoring and stress monitoring are in the lower part of the wedge. Near the instability, the upper part of the wedge is the sensitive part of displacement monitoring, and the upper middle part of the wedge is the stress monitoring sensitive part. In the early stage of the wedge instability process, the monitored stress value is significantly increased compared with the initial state, and compared with displacement monitoring, the feedback of stress monitoring is more advanced, and can respond to the change of slope more timely. The research results can provide reference for the safety monitoring of the rock slope wedge.