As oil-free rotor support technology, active magnetic bearings (AMBs) are increasingly applied in turbinmachinery, including steam turbines. The compact multiple disksrotor bearing system of maglev steam turbines leads to complicated dynamic behaviors, which is the basis of AMBs controllers design. In this paper, an analytical modeling method is proposed to describe the dynamic characteristics of AMBs-rotor system of maglev steam turbines. The analytic rotor dynamic model consists of multiple rigid disks on a flexible shaft and AMBs. In modeling the rotor bearing system, the flexible shaft is discretized by Euler Bernoulli beam elements. The connection between rigid disks and flexible shaft is equivalent to spring dampers. Angular stiffness and angular damping coefficients are introduced to model the spring dampers and identified by 3D finite element simulation results. The bearings force takes the control system of AMBs into consideration. Moreover, experiments of a test rig are carried out. The results show that the proposed analytical rotor dynamic modeling method is effective.