This paper investigates the failure modes of serially connected isolation system that the rubber bearing connected with the basement column, under large deformation. Base on Haringx theory and Timoshenko beam modal, the geometrically non-linear equations of serially connected isolation system with one end clamped and the other glided, subjected to a terminal force, are formulated. By using differential quadrature element method (DQEM), the non-linear equations are solved numerically and the configurations of the deformed column are presented. The results show that the large deformation of serially connected isolation system mainly occurred in the rubber bearings. The buckling of rubber bearing is the main failure mode of the serially connected isolated system.