Abstract: [Objective] With the frequent occurrence of landslide disasters in China, it is indispensable to strengthen the research on unstable rock mass and unstable slopes, due to the inability to quantify or other shortcomings of the traditional analysis methods. In order to improve the traditional scheme, we adopt the non-contact measurement method to obtain and analyse the parameters of wedge-shaped unstable rock mass, and analyse the stability of wedge-shaped unstable rock mass under different working conditions by the obtained parameters. [Methods] Taking the wedge-shaped unstable rock mass in the upper reservoir of a pumped storage power station as an example, this paper reveals the basic features and stability influencing factors of the unstable rock mass based on the fine engineering geological field investigation. A long-distance 3D laser scanning system is used to obtain high-precision point cloud data of the slope. The spatial parameters of the wedge-shaped unstable rock mass are obtained through preprocessing, and the plane where the critical surface is located is also obtained through least-squares fitting to determine the slope angle and slope height of the wedge-shaped body. The point cloud is fitted with local point cloud to determine the normal vector, and the obtained normal vector is calculated to find out the discontinuity occurrence. The Alpha shape method is used to calculate the volume of the unstable rock mass, and the most suitable radius parameter is obtained by comparing with the actual unstable rock mass. Then the limit equilibrium method is used to evaluate the stability of the unstable rock mass. [Results] Through the experiment to get different states of the rock mass capacity, cohesion, friction angle, etc., combined with access to the specification to determine the seismic coefficient and calculation of the geometric parameters, the results show that: in the natural conditions, the wedge-shaped unstable rock stability coefficient of 1.131 is in an essentially stable state; in the rainstorm conditions, the stability coefficient of the wedge-shaped unstable rock body 0.896, in a state of instability; in the seismic condition, the wedge-shaped unstable rock body The stability coefficient of the wedge is 0.917, which is unstable. [Conclusion] In this paper, non-contact measurement and intelligent recognition are applied to the stability analysis of wedge-shaped unstable rock mass, and the overall time taken is 102 minutes, which greatly improves the stability analysis efficiency and reduces the risk of engineering construction.