Due to the long-term action of natural forces, the cultural heritages of grotto temples and rock carving are extremely vulnerable to tectonic stress, crack expansion, rainwater erosion, etc., resulting in serious rock mass instability. Taking the Cliff Statues of Shizhuan Mountain in Dazu Rock Carvings as an example, through field surveys and laboratory tests, the engineering geological conditions of the carving area and the macro mechanical properties of regional rock are obtained, and the stability of the dangerous rock mass under the two main failure modes of dumping and sliding are respectively evaluated by combining qualitative and quantitative methods, and reinforcement schemes are formulated. The calculation results show that the stability safety factors of dangerous rock masses of dumping and sliding are 1.39 and 1.20 respectively under the influence of seismic factors. Considering the particularity of preservation status of cultural relics and the tourist visit services in the grotto area, a comprehensive treatment of "bolt reinforcement + stone masonry + crack grouting + old treatment" is adopted. By monitoring the displacement and stress, the deformation of dangerous rock masses of dumping and sliding are controlled within the range of 3 mm and 6 mm after reinforcement, which verifies the effectiveness of the reinforcement scheme and minimizes the major danger of Shizhuan Mountain cliff statues in time to ensure the safety of tourists and cultural relics.