The 3-D FEM numerical model of foundation for wind power turbine generator system is created, based on the platform of ANSYS. The non-linear contact between the foundation stub part and concrete is introduced. The internal mechanical characteristics and laws are studied when the tower structure is bearing the random direction wind load. The laws of the settlement and deformation of the tower are discussed and the contact status of contact areas is attained. The numerical analysis which considers the contact status and material nonlinearity is more rational. The research results provide the indigenous design and optimization of our nation scientific basis.