Abstract: The mechanism research at present mainly pauses in the qualitative description.The quantitative index is lack in the description of sliding mechanism.Inversion analysis is an important means to determine the strength parameter of sliding zone.Rigid body limit equilibrium method and a global safety factor are used in this paper.So,strength parameter has no direct relation with the sliding mechanism.Three-dimensional stress state and slide direction of the slip layer zone are obtained by numerical computation.Base on the Mohr-Coulomb Strength Criterion,a point safety factor as the ratio of the shear strength of the slip zone to the shear stress parallel to the gliding direction is defined.The safety factor of the landslide as the weighted average value of the zone point safety factor with its zone is defined.The sliding mechanism is studied quantitatively by means of analyzing the distribution of the zone point safety factor.Landslide stability can be evaluated through the safety factor.So a relationship between the sliding mechanism and stability factor is established.In the inversion analysis,the sliding mechanism and stability can be satisfied simultaneously.So the corresponding strength parameter is a reasonable inversion result.This paper uses the example of the large scale geomechanics model test for K49 landslide in Wanliang highway to illustrate the method and procedure for strength parameter inversion of sliding zone based on sliding mechanism analysis.The rationality of this method is shown by the applications.