Magnetorheological (MR) dampers are one of the most promising devices for mitigation of vibration of engineering structures due to earthquakes and wind excitation. In this paper, a compact two-column model of an MR fluid is proposed in order to formulate a general solution for calculation of the yield shear stress of an MR fluid. The magnetic induction intensity in the damping gap, which is the key parameter of the compact two-column model, is determined through simulation of the magnetic circuit of the MR damper. To verify the effectiveness and significance of the proposed model, damping forces calculated based on the proposed model and the traditional single-chain model are compared with the experimental data. Results show that the proposed compact two-column model is more accurate and that it can describe the rheological properties of the MR fluids very well.