The nonlinear stability analysis of the short box, the long box and the whole wing structure were compared by MARC2003 nonlinear finite element calculation software. The results indicated they were not appropriate to substitute the important part for the whole structure and use the node displacements of the linear calculation as the boundary conditions of the nonlinear analysis. This technique should not be used for the stability design. By comparing the differences of the deflection and the torsion angle between the linear and nonlinear analysis, it was concluded that the nonlinearity seldom influenced the deflection whereas it could remarkably influence the torsion angle. In conclusion, the nonlinear impact must be considered in the torsion stiffness and aeroelastic designs of the wing.