<p>Most traditional physical models for magnetorheological (MR) dampers are quasi-static models based on a parallel plate model, which is restricted by structure parameters because the annular gap is required to be far less than the inner diameter of the cylinder. Meanwhile, ignoring the dynamic properties of MR dampers, the quasi-static model produces considerable error under dynamic excitation and its accuracy needs to be improved. To counter the problems above, a theoretical model taking both the inertia effect and the hysteresis into consideration was developed for MR dampers which divided the mechanical properties into the hysteretic stage and the non-hysteretic stage. Based on the particle-chain theory, the damping behavior of the MR damper in the hysteretic stage are analyzed theoretically. The average acceleration method is adopted to describe the inertia effect, the theoretical model of the MR damper in the non-hysteretic stage was developed based on the annular channel model. The dynamic behavior of the MR damper at the non-hysteretic stage are systematically analyzed under different structural parameters and excitation conditions. Further, the fabricated MR damper was tested under sinusoidal excitation and it was found that the influence of the inertia effect diminishes and hysteresis effect increases with increasing applied currents. Comparative analysis of measured data and theoretical results indicates that the proposed model can adequately capture the dynamic behavior of the MR damper.</p>