Abstract: High-position unstable rock masses above Shanyi village in the Western Hills of Kunming pose a serious threat to the safety of residents and critical transportation infrastructure below. This study aims to evaluate their stability, predict potential post-failure hazards, and propose effective mitigation measures to support regional disaster prevention and management. The basic characteristics of unstable rock masses were identified through 3D UAV-based oblique photogrammetry and field investigations. Stability coefficients under three scenarios, i.e. natural conditions, rainstorm conditions, and coupled rainstorm−earthquake conditions, were quantitatively calculated using the Limit Equilibrium Method. Subsequently, RocFall was employed to simulate the runout trajectories of rockfalls under rainfall and seismic triggers, enabling zone-specific risk assessment and mitigation planning. The results demonstrate that: (1) the study area is divided into four hazardous zones (A, B, C, D), containing a total of 29 individual unstable rock blocks, most classified as ultra-high-position. Their dominant failure modes include sliding, toppling, and falling. (2) Stability analysis revealed a sharp degradation under external triggers: under natural conditions, the factor of safety (FOS) ranges from 1.16 to 92.2, indicating stable to extremely stable states; under heavy rainfall, FOS drops to 0.79−2.07, with many blocks becoming unstable or marginally stable; under coupled rainfall−earthquake conditions, FOS further declines to 0.46−1.36, and 68.7% of the blocks are classified as unstable. (3) Trajectory simulations for these unstable scenarios demonstrate that collapsing rock can directly impact residential houses, and secondary bounces may reach the adjacent highway, posing a severe threat to road safety. The unstable rock masses in the study area exhibits high failure risk under rainstorm and seismic conditions, posing a significant threat to the personnel and infrastructure below. While engineering measures such as zoned anchoring and protective barriers are technically feasible, c comprehensive consideration of ecological conservation in the Western Hills Scenic Area, construction accessibility, and long-term safety leads to the recommendation of complete village relocation as the optimal solution.