The conception and method of multi-grid is brought forward; the mesh of finite element analysis and the sliding surface’s mesh are deal with as two unattached mesh

and the sliding surface’s mesh can go across any finite elements. In this way

discretionary sliding blocks’ analysis can be done with a set of finite element mesh and a set of stress results. The calculation efficiency of multi-grid method is emphatically analyzed. The 3D multi-grid method is applied to a typical 3-D quadrangular and Jinping Project high slope. Numerical results show that the properly adjusting the mesh of the finite element models and sliding surfaces can effectively improve the precision and calculation efficiency of this method; especially for the large scale structure. Finally

the stability of Jinping Project high slope is analyzed using the second way of multi-grid method.