Strong toppling deformed bodies in reservoir area often destabilize in a specific mode during storage period. According to the instability characteristics of site slope,the failure mode is analyzed as "upper tension-lower shear" failure and sliding surface obviously segmented. Based on the traditional Sarma method,considering the strength reduction of saturated rock mass and hydrostatic pressure,the Sarma method is improved by adjusting the strength reduction coefficient of rock strata. Fortran is used as a platform to compile a program for stability analysis of strongly toppling deformed bodies. The mechanical model and analysis method are validated by a slope example of Miaowei Hydropower Station,and its accuracy is verified by comparing with the results of discrete element simulation. The parameter analysis results show that the stability of the toppling deformation body is negatively correlated with natural slope angle and the stability of the slope with more soft rock will be greatly reduced after impoundment.