Due to the long-term action of natural forces, the cultural heritages of grotto temples and stone 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 a comprehensive analysis of the engineering geological conditions of the stone carving area and the macro mechanical properties of regional rock. On this basis, the quantitative evaluation of the dangerous rock masses under the two dumping (R1) and slipping (R2) failure modes is carried out respectively, the calculation results show that the stability safety factors of R1 and R2 dangerous rock mass 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, which eliminates the major danger of Shizhuan Mountain cliff statues in time to ensure the safety of tourists and cultural relics. By monitoring the displacement and stress, the deformation of R1 and R2 dangerous rock masses are controlled within the range of 3 mm and 6 mm after reinforcement, which verifies the effectiveness of the reinforcement scheme. It provides a certain theoretical basis for the prevention and reinforcement of disease of dangerous rock mass in the grotto area.