Abstract: The stability of open-pit mine slope under complex geological conditions is a key problem to be solved urgently in practical engineering. Judging the sensitivity of influencing factors is the basis for solving the problem. In order to systematically quantify the sensitivity of each influencing factor, this study constructed a comprehensive analysis method combining orthogonal test design and grey correlation analysis. Based on a typical open-pit mine slope, the influence of six parameters of weak interlayer dip angle α, cohesion c, internal friction angle φ, thickness h, burial depth d and fault dip angle β on slope stability was explored by numerical simulation system. The results show that the orthogonal test and grey correlation analysis have a highly consistent sensitivity ranking : internal friction angle of weak interlayer > buried depth of weak interlayer > fault dip angle > cohesion of weak interlayer > dip angle of weak interlayer > thickness of weak interlayer, which confirms the reliability of the method framework and the scientificity of the conclusion. Further, the study reveals the nonlinear influence law of fault dip angle change on stability : with the increase of fault dip angle, the slope stability increases, and the shear strain in the slope gradually expands, which leads to the gradual weakening of the influence of fault on slope stability. This rule is significantly consistent with the accurate characterization of the modified Gompertz model in this paper. This study provides a standardized analysis framework for the identification of the main control factors of complex slopes, and has theoretical guiding significance for the accurate prevention and control of slope disasters.