Abstract: This paper examines the effects of parameters in the generalized Hoek-Brown failure criterion on the mechanical parameters of slope rock mass using orthogonal test method. It gives a comprehensive analysis of various factors and effectively explains the limitation of single-factor method. Sensibility analysis of the criterion parameters based on the orthogonal test is done within the slope of 5# abutment in Longqiao Extra-large Bridge. It is found that the Geological Strength Index (GSI) influences the rock mass deformation parameter Em significantly, and the compressive strength ci and disturbance factor of rock mass D have greater impact on the rock mass strength parameters C、. In summary, the index GSI and ci are more sensitive to the mechanical parameters of rock mass comparing to disturbance factor of rock mass D,and then mi;There is no interaction between the criterion parameters, and they are relatively independent.