Abstract: The load capacity and stiffness (current stiffness and position stiffness) are the primary performance criterions of an active magnetic bearing (AMB) system and depend on the size and geometry of the AMB and the performance of the control system as well. It is imperative to investigate the performance of the AMB in a wide range of operation and control condition. Thus a nonlinear two-dimensional finite element method (FEM) is used to predict and calculate the force versus the control current characteristics of a journal active magnetic bearing. The current stiffness and position stiffness are calculated at different operation conditions, and the load capacity of the AMB is predicted making use of the established FEM model and compared with that based on the linearized model of the AMB. It has been found that the calculated results based on the FEM agree well with the experimental ones and can be used to guide the design and analysis of the radial active magnetic bearing.