Abstract: Based on the engineering geologic section model and rock mass parameter of left bank slope of Longtan Hydropower Station,the influential factors were analyzed with orthogonal analysis of toppling rock slope,the range of dominance of toppling slope,was proposed and the topping condition with displacement vector angle in the same nod of different models were also analyzed.Through contrast with the practical engineering case,the obtained results were shown to be applicable as a quick analysis method for failure mode of toppling rock slope.